Conor McGregor has set the internet alight on Saturday after a very revealing weigh-in ahead of his clash with Floyd Mayweather.
After stripping down to his boxer briefs for the weigh-in, 'Mystic Mac', as McGregor is known, left little to the imagination as he faced off with the undefeated boxing legend known as Money.
Muscles were not the only thing bulging during the spectacular stare-down, with veins visibly popping in McGregor's neck as he screamed in the face of his more composed opponent.
Mayweather wore a special pair of underwear himself - an Irish-green pair branded with PaddyPower and the catchphrase 'Always bet on black'.
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Conor McGregor has set the internet on fire after a very revealing weigh-in ahead of his clash with Floyd Mayweather on Saturday night
The Irish UFC star accused the undefeated Mayweather of 'being in the worst shape of his life and scared' ahead of fight night
The Irish fans cheer as Conor McGregor successfully makes weight ahead of the massive box-office boxing clash tonight
After stripping down to his boxer briefs Mystic Mac left little to the imagination as he faced off with the undefeated boxing legend known as Money
A fan poses with the Money Belt, the title which will be awarded to the winner of the much-hyped contest between McGregor and Mayweather
Conor McGregor holds the Irish flag during weigh ins, while also sporting Beats By Dre headphones with Ireland motifs
McGregor spectacularly defied Floyd Mayweather's prediction that he would fail to make the weight as they came to the scales before their mega-millions extravaganza - prompting loud cheers from the Irish crowd
The outrageous display sparked a storm of shocked comments on social media, with some users saying they understood the Irishman's willingness to walk around in his underwear.
'McGregor was a little excited during this weigh in,' said one Twitter user. 'McGregor has got a banana in his pants loool how excited is he?!' wrote another.
'Now I get why McGregor left his pants off after the weigh-in #heproud' was another fan's reaction.
McGregor spectacularly defied Floyd Mayweather's prediction that he would fail to make the weight as they came to the scales before their mega-millions extravaganza.
The Notorious weighed in a full pound under the 154lbs weight limit. Mayweather was significantly but expectedly lighter at 149 1/2 lbs.
That put paid to the notion that his training may have been compromised by late, nightly visits to his strip club. McGregor returned to screaming at Mayweather come the stare down.
'He looks like dog s***,' said McGregor of his opponent. 'You know that. He looks blown out. Full of water. He's not going to keep my pace. Trust me on that. That’s the worst shape I’ve ever seen him.'
ALL THE ODDS, TIPS AND BEST BETS AHEAD OF FIGHT
Floyd Mayweather and Conor McGregor's bout has garnered such interest that it is set to smash all previous betting records.
As the biggest market of all time, the punters are flocking to make a quick buck, with most opting for the underdog.
McGregor's odds have shortened dramatically, but where can the best value be found ahead of Saturday's clash?
The most popular market, particularly for casual gamblers is simply, who they are backing to have their hand raised at the end.
SkyBet have the best odds on Mayweather to bring it home (1/4) and also offer the best value for his opponent to shock the world (7/2).
Pictured: Irish fans enjoy a big night ahead of the fight. Floyd Mayweather and Conor McGregor's bout has garnered such interest that it is set to smash all previous betting records
One bettor staked £650,000 on a McGregor victory at 10/3 – which would return winnings of more than £2.8million. And Paddy Power estimate they would lose £10million if the 'Notorious' earns the belt.
Most popular method of winning
Both men have predicted a KO of their opponent, with McGregor foreseeing his victory inside four rounds.
His opponent simply promised a knockout so one of them, and plenty of gamblers will be wrong.
Mayweather by KO/TKO (8/11, BetFred) and decision (11/4, Coral) come out on top value.
Our tips for the fight (All Paddy Power)
Many believe the Irishman to have a power advantage, citing his opponent's age, brittle hands, and recent track record of going the distance.
But Mayweather is coming up against vastly experienced boxers, not a man in his first professional bout, with that said, it may be worth getting on the 49-0 star to win by KO in the first three rounds (11/2)
If the veteran doesn't have the ability to inflict enough damage by the time 12 rounds are up, he is surely going to have outboxed McGregor so a decision win (11/4) could be well worth a dabble.
The 'Notorious' signed a strict contract, forbidding him to land any MMA style strikes outlawed under the Queensbury Rules. And yet the aggressive Irishman could be disqualified in a number of other ways if he becomes frustrated, it might be a risk worth taking for punters (13/2).
If the most-hyped contest of the year manages to live up to expectations with a dramatic climax, Mayweather could tire the 28-year-old down by the later rounds so a stoppage between rounds 10-12 (13/2) might be a solid option.
Outlandish bets (William Hill)
McGregor to be disqualified for throwing a kick (12/1)
Both fighters to be knocked-out simultaneously (250/1)
McGregor to not land a punch (50/1)
The outrageous display sparked a storm of shocked comments on social media, with some users saying they understood McGregor's willingness to walk around with no pants on
The two fighters posed for the assembled media following the weigh-in in front of a raucous crowd at the T-Mobile Arena
Even before removing his green track-pants UFC superstar Conor McGregor's appearance at the weigh-in was very revealing
Floyd Mayweather and Conor McGregor both weighed in under the 154lb super-welterweight limit for their fight on Saturday
Mayweather, 40, provocatively wore green PaddyPower boxer shorts which bore the catchphrase 'always bet on black'
Here, former world champion Johnny Nelson provides the ultimate guide to the money-spinning mega-fight
'I'm going to breeze through him, trust me on that. I'm a professional, I make weight - its sacrifice, dedication, focus, but I make it. I'm ready.
'I'm going to be a lot bigger than him tomorrow night, maybe closer to 170.'
McGregor received a boisterous Irish welcome as he entered the T-Mobile Arena draped in his country's flag and sporting glasses hinged with sun lenses.
Mayweather responded to his mixed reception by pointing to his white 'The Best Ever' baseball cap and T-shirt, smiling broadly and then warning fans of the Irishman: 'This will be Conor McGregor's last fight also.'
Mayweather brushed off any potential advantage for McGregor over the size difference though after ending his two-year retirement.
'Weight doesn't win fights. Fighting wins fights,' said the American.
A sizeable Irish contingent has travelled to Vegas to cheer the 29-year-old in action and he repeatedly saluted his supporters.
'You can't beat us, we've already taken over what we want,' said McGregor.
'Las Vegas is Ireland now.'
RULES OF THE FIGHT: THE DIFFERENCES BETWEEN BOXING AND UFC
McGregor and Mayweather will fight under boxing rules, giving the 'Money Man' (left) a clear advantage
Floyd Mayweather fights Conor McGregor in the Irishman's professional boxing debut at Las Vegas' T-Mobile Arena on Saturday.
McGregor and Mayweather will fight under boxing rules, giving the 'Money Man' a clear advantage.
That obviously means the Irishman will not be allowed to kick, elbow or use any of his usual take-down moves.
Boxing etiquette requires the pair to touch gloves before the first and last round – but those gloves will be smaller than their normal size, weighing just eight-ounces instead of ten, to increase McGregor's advantage. He normally fights with four-ounce gloves that are fingerless with very little padding.
Other than that the normal rules apply: Three judges will decide the points each three-minute round. The winner of the round is given 10 points and the loser takes nine.
However, a boxer loses a point if they are 'floored'.
The fight could, however, be ended swiftly with a knockout if the opponent can't get up after 10 seconds of falling to the ground.
Here are the significant differences between boxing and the Ultimate Fighting Championship:
LENGTH AND NUMBER OF ROUNDS
A high-level boxing match is almost always scheduled for 12 three-minute rounds. When a boxer makes his professional debut, they are often scheduled for four three-minute rounds, which is usually gradually increased to six, eight, 10 and then finally 12. In women's boxing, two-minute rounds are largely favoured. Boxing debutant McGregor will fight over 12.
UFC rules dictate that each non-championship contest is to be scheduled for three five-minute rounds. A championship contest is for five five-minute rounds.
In both sports, there is a rest period of one minute between rounds.
Advertisements for the bout between boxer Floyd Mayweather Jr. and UFC lightweight champion Conor McGregor are displayed on the side of T-Mobile Arena in Las Vegas, Nevada
THE NATURE OF THE FIGHT
Boxers are officially only allowed to attack their opponents through punching, and even excessive clenching is discouraged and monitored by the referee. If a boxer is knocked down, his opponent is not allowed to resume attacking him until he has returned to his feet and has the referee's permission to do so.
In UFC, fighters can box, grapple, wrestle, kick-box, and continue to strike their opponent while they have been knocked down.
SIZE AND SHAPE OF THE RING
A boxing ring, within the rules of the British Boxing Board of Control, should have four ropes and be between 16-20 square feet.
A UFC 'octagon' must be between a minimum of 20 square feet and a maximum of 32. It is also surrounded by a fence.
Boxers regularly provide their own cuts man, and one of their choosing. The UFC, however, provide one for each corner, and that same cuts man works the same corner for every fight of each event.
Profiles of boxing legend Floyd Mayweather and mixed martial arts icon Conor McGregor, who face each other in Las Vegas
Unlike in boxing, UFC fighters are forbidden by their contracts to pursue their own sponsorship deals. They presently have an overall sponsorship in place with Reebok.
In boxing, a fighter must weigh in at the scheduled time and if he or she is overweight, has an hour to return and achieve the correct weight. If they remain overweight after an hour they do not receive a further chance, though the fight may still proceed.
In the UFC, on the day before a fight, a fighter has a window of four hours in which they can make weight at their own convenience.
A boxing glove covers the entire hand, and in fights between the flyweight and welterweight divisions, 8oz gloves are generally worn.
In the UFC, a fighter's fingers remain exposed, and the glove generally weighs between 4oz and 6oz.
McGregor, who headed to the scales draped in the Irish flag, received immense support from those inside the T-Mobile Arena
McGregor took to the scales first and, despite reports he was struggling to make weight, came in under the 154lb limit
The Irishman had to be held back by security staff as the 40-year-old Mayweather weighed in well under the 154lbs limit
McGregor screamed in the face of his undefeated opponent as they went face-to-face before their money-spinning bout
The undefeated boxer stared and pointed at his Irish opponent as he tipped the scales well under the 154lb weight limit
McGregor, who hinted he will weigh around 170lbs on Saturday, promised to stand in the centre of the T-Mobile Arena ring
Mayweather was not phased by the partisan crowd though - even daring to wear Paddy Power green underwear.
HOW TO WATCH THE BIG FIGHT
The event will be broadcast on Sky Sports Box Office at a cost of £19.95 in the UK or 24.95 euros for McGregor's Republic of Ireland compatriots.
Punters across the pond will have to fork out 89.99 US dollars for standard definition and 99.99 US dollars in HD.
It is likely to start around 5am UK time (9pm in Vegas) - but it may even be 5.30am when the first bell sounds.
He said: 'The fans can't fight for him. It comes down to the two competitiors.
'In the 49 times I won out there, it was one on one.'
The two were a stark contrast in their behaviour as they posed head-to-head for the cameras after the weigh-in.
Mayweather was cool, calm and collected as he stared at McGregor, while the Irishman laughed, smiled and launched a verbal assault of trash talk.
It was only when they broke away that Mayweather broke into a smile and laughed at the UFC lightweight champion's remarks.
But after an undefeated record as a former five-weight world champion, Mayweather stressed how he has been here and done it all before.
'I've been here before. I know what it takes when it's a fight of this magnitude,' said Mayweather.
'I've done a lot of this (chatting) he's done a lot of this, but tomorrow it comes down to the fighters.'
The real Conor McGregor... A former plumber who cried in defeat and has gone from €188-a-week dole to £62m fight in four years
The pawnbroker who made Conor McGregor cry is dredging up an old transaction. He wrestles with his memory but can't quite get a choke hold on the figures.
'They paid me €400,' Artemij Sitenkov tells Sportsmail. 'Or it might have been 500. It was a long time ago. At the time, I didn't think anyone would care about it now, nine years on.'
With that, the 34-year-old laughs down the phone from his home in Lithuania. He's happy enough, this jack of all trades who manages gyms, trades antiques and runs a pawn shop.
He also does mixed martial arts when he needs extra cash, balancing 16 defeats with 15 wins from Kazakhstan to Ireland, where he rocked up in June 2008 to a hall in Drimnagh, Dublin.
It was McGregor's third professional MMA fight and his first defeat, with the former plumber tapping out after 69 seconds.
'He was crying after and was being comforted by his trainer,' Sitenkov says. 'I went home and didn't think of him again. Then, a few years later, wow. UFC, fame, everything. This thing with Floyd Mayweather, wow.'
McGregor's appearance has changed a lot in the past four years, as his career has flourished in and out of the octagon
Conor McGregor, pictured with girlfriend Dee Devlin, has come a long way in a short time, starting life as a plumber
It's the anomaly that looks like a mismatch at best and a freak show at worst. But how has a non-boxer, who was drawing dole cheques in 2013, talked and grappled his way to a payday worth in excess of £60million?
Not much of it makes sense. Except, that is, to those in Dublin who know McGregor best and who know about the self-help book, the gorilla video and the women's skincare products. To them, their mad friend has had this date from the start.
Phil Sutcliffe is grinning in his recollections. He runs the Crumlin Boxing Club, a mile from where McGregor grew up.
It is not the grenade-ravaged hell of a recent ESPN profile but it does get tasty, and for McGregor that meant being hassled by a group of six lads one day in 1999, when he was 11.
The tale goes that he did an Ali shuffle before throwing a left hook and he took a pasting in return. That soon led him to the boxing gym.
'He had been playing football,' says Sutcliffe. 'He had his muddy boots on and walked straight over our clean floor to hit a bag. We told him to get out.
'He was back a few days later in kit and that was him started.'
Conor McGregor was an Irish Under 16 schoolboy boxing champion and he trained at Crumlin Boxing Club (pictured)
'The Notorious' (pictured with girldfriend Dee Devlin) now owns a £2million property, just four years after picking up his last dole cheque
In the home of Mags, his mother, and his father Tony, a taxi driver for 26 years, is a trophy of a boxer with its left hand snapped off.
The son peaked as Irish Under 16 schoolboy champion and it is interesting to consider what path his career might have taken if the family had not dragged McGregor screaming to the calmer suburb of Lucan when he was 16.
He continued to blag lifts back to his club for a while, but, significantly, kick-boxing became a rival fascination and then there were also the conversations with Tom Egan at his new school.
They had seen the Ultimate Fighter cable show and got hooked on a combat with fewer limits. Eventually it came at the expense of boxing.
'Conor and me were training at Crumlin the same time — he was a very good boxer,' says Jamie Kavanagh, a 20-1-1 pro. 'We're still friends and who knows what he might have gone on to in it.
McGregor, pictured here aged 12, grew up in Dublin with parents Tony and Margaret
'He wasn't as much into the technical side, but his eyes lit up in a fight.
'He didn't get in many street fights compared to some — I can only remember one when we were away with the club in Malaga. Some guys started and we didn't lose, put it that way.
'The thing with Conor, he has always had great focus. He really could have boxed to a top level but with the intensity this guy has, you wouldn't have bet against him at any sport.'
McGregor first walked into John Kavanagh's Straight Blast Gym for MMA in 2006.
It was a year when two other important things happened — he left school at 17 to be a plumber and Rhonda Byrne's book, The Secret, came out, espousing the power of positive thinking.
Upon reading it, McGregor entered Kavanagh's gym determined to make an impression and famously clattered Owen Roddy, the top dog, in sparring.
Then he was put in with Aisling Daly, a female star of UFC, and floored her with an excessively hard body shot. At that point, Kavanagh joined McGregor on the mat and battered him.
'It is not the done thing to beat up on people in the gym and John was making a point,' Daly says.
McGregor trained alongside his work as an apprentice plumber, which saw him leave home at 5am each morning. He hated it and quit after 18 months, going on the dole for €188 a week, all eyes on MMA. But even then it was far from straightforward.
McGregor's first fight was in 2007 and when he lost to Sitenkov a year later he was still making €100 a go. He fled the venue with €500 of ticket money he owed Kavanagh and appeared finished until McGregor's mother begged the coach to talk her 19-year-old son out of his bedroom.
Kavanagh wrote off the debt and tweaked something in McGregor's mind.
'He had something in him — this obsession to get better, to make a different life,' Daly says. 'You have never seen anything like it.'
It is the recurring term used by all who know him. John Kavanagh tells of the time McGregor sent him footage of gorillas wrestling and asked if their holds were transferable. McGregor became the only fighter to have his own key to the gym because Kavanagh grew tired of getting called for it at all hours of the night.
McGregor (pictured with Nate Diaz) cried after losing to Sitenkov, but he has since established himself as the star of UFC
McGregor's relationship with his current coach John Kavanagh (pictured foreground, with sparring partner Artem Lobov) began way back in 2006
Gradually, the wins mounted up until he became a two-weight world champion in the Cage Warriors branch of MMA. But while the rapidly-growing UFC is familiar to millions, Cage Warriors and McGregor were invisible.
'Funny thing is, his personality then, when he had nothing, was the same as now,' Daly says.
'At the gym, I had a female changing room and every day he'd swagger out in a tiny towel, his hair smelling like my nice shampoo and wearing my moisturisers. He always had loads of charisma, and if you have charisma and can fight, you are on to something. Look at Ali.'
By 2013, McGregor was still broke. He was a good fighter and talker but was stranded on a tiny platform.
'No one doubted what he would do with the right break,' Daly says.
And then he got it — a call to appear on a UFC card in Stockholm. Before he flew, he stopped to collect his €188 dole cheque.
Four years on, McGregor is a two-weight UFC world champion, has a speedboat called 188 and owns a £2m property with his long-time girlfriend. His 2016 earnings of £26m were ranked by Forbes alongside Gareth Bale's.
How? Because the UFC love bombast and violence in ways the rest of society often dislikes and no one does either quite like McGregor, the snarling face of a snarling brand. His gym mates tell tales of unseen humility — he calls a 13-year-old kick-boxer Nate Kelly 'Nate the great' and gives him pointers.
But it is the face he presents to the public that has made this fight. It remains to be seen if it all ends in tears again, though the sense around Crumlin is that their man has already won.
McGregor lost to MMA fighter Artemij Sitenkov (pictured auctioning the pants he wore when beating the Irish star), who was paid just €400 to fight him in 2008