(CNN) — “It’s official!”
The two words published on Floyd Mayweather’s Instagram account on Tuesday were all it took to send the sporting world into a frenzy.
The August 26 rumble in Las Vegas between Mayweather — boxing’s top-ever earner coming out of retirement with a 49-0 record — and UFC lightweight champion Conor McGregor, will likely be the biggest payday in the history of the sport.
“Bring him over to the boxing world and I’ll show him what it’s like, easy” Mayweather — who has reportedly grossed $700 million in his career — told reporters in January, when speculation first brewed about the matchup.
Forty-year-old Mayweather, who last fought in September 2015 against Andre Berto, will give up an inch in height and two inches of reach to 28-year-old McGregor.
McGregor began as a youth boxer in his native city of Dublin, but has never boxed professionally. The left-hander is known for his aggressive style and counterpunching, earning 18 of his 21 UFC wins by knockout.
“People always think it’s a game or it’s an act,” McGregor — a 6/1 underdog according to bookmakers’ opening lines — said. “I’m just simply the best fighter, that’s it.”
His three career losses — including a March, 2016 fall to Nate Diaz — have all come by way of submission. (He avenged the Diaz loss with a decision victory five months later.)
McGregor announced his signing on Tuesday with an Instagram post appearing to poke fun of Mayweather, showing a split photo of himself and Floyd Mayweather Sr.
Although Mayweather’s father, a former boxer and top trainer, returned to his son’s camp of late, the two were estranged for many years. Mayweather Sr. trained the likes of Oscar De La Hoya and Ricky Hatton instead. It is not clear whether father and son will be reunited for another bout.
Biggest purse in boxing history?
Given the two-year build-up of social media sparring between the flashy opponents, the heavyweight purse at stake in this super welterweight bout was simply too much to resist.
“When you’re talking about $500 million projections in terms of financials, it’s the fight that had to happen within the sports industry,” Scott Hurst, MMA expert and co-founder of the website Real Sport, told CNN’s World Sport show.
Numbers have yet to be confirmed, but Mayweather has previously stated he would take no less than $100 million guaranteed, and offered $15 million to McGregor. In his previous mega-bout, a 2015 contest against Manny Pacquiao, Mayweather grossed a record $500 million, according to the two camps and the TV networks involved.
In January, McGregor boldly claimed a fight between him and Mayweather would make $1 billion.
“One thing we can get excited for is that we’ve got Mayweather and McGregor, two of the best trash talkers in the world,” Hurst adds. “I believe the run-up to the fight and the build-up is going to be 100 times better than the fight itself.”
The lack of cohesion between the two sports appears to be a disadvantage for Irishman McGregor, who will be fighting on his opponent’s terms.
It’s not quite Jessie Owens racing against horse — a contest which Owens won, incidentally — or Muhammed Ali farcically fighting Japanese wrestler Antonio Inoki in a 1976 exhibition, but it’s an odd pairing nonetheless.
“If you’re running a marathon, then the marathon runner is going to win against a sprinter 99.9% of the time,” says Hurst. “Unless Mayweather falls out of the ring, or doesn’t turn up for the fight, I think it’s very unlikely that the 49-0, undefeated, pound-for-pound best boxer is going to lose to McGregor with no boxing experience whatsoever.”
“He will last as long as Mayweather will allow him to last for,” legendary boxing trainer Teddy Atlas told ESPN.
“All these UFC guys, they are very tough, tough guys. They have grappling skills and (if) they get you on the floor, you know, for the average athlete it’s all over,” he added. “But as far as strictly adhering to boxing rules? No contest baby.”
“They are cavemen, they would not beat C-level fighters.”
One point that is getting little attention so far is that Mayweather is coming out of retirement at risk to his undefeated 49-0 record, an unblemished mark which currently ties former heavyweight champion Rocky Marciano.
“That’s the easiest road to a 50th win in the history of the sport,” says Hurst.