Undefeated boxer Floyd Mayweather, Jr., is putting his undefeated record on the line once more.

After months of ceaseless hype, "Money" will finally come out of retirement to step into the ring against Conor McGregor, the Irish MMA superstar and current UFC lightweight champion, in a to-be-decided venue in Las Vegas on August 26.

Mayweather confirmed the fight on Twitter, writing: "IT'S OFFICIAL!!!"

McGregor wasted no time in hyping the fight, tweeting "THE FIGHT IS ON" accompanied of a picture of himself with Floyd Mayweather, Sr.

The fight confirmation was first reported Wednesday afternoon by Yahoo! Sports reporter Kevin Iole. It had been rumored for months, and only recently did UFC President Dana White offer some solid business information on the deal that, for months, seemed like a pipe dream designed to keep people talking—particularly the fighters themselves. (McGregor said in April that boxers would be "dismantled and killed" in a street fight.) On April 19, White said the contract would be coming 'in a few days.' On May 18, White said McGregor's 'side [was] done' in the fight. Only this week did Mayweather's team seem to confirm that the fight would be a concrete possibility, with Mayweather Promotions booking—and then canceling—the MGM Grand for a boxing match on August 26.

The Mayweather-McGregor fight had been rumored for months, and represents an unusual step for both fighters. McGregor, very much in his prime atop the UFC lightweight division, will be forced to put his southpaw punching ability against one of the greatest boxers of all time. Mayweather, meanwhile, will be coming out of retirement, and risking his perfect 49–0 record against a relatively inexperienced boxer—albeit one who is also a top-notch MMA brawler—who is still 12 years his junior.

Regardless of the unusual circumstances, the megafight is sure to generate an enormous payout. Oddsmakers had long established McGregor as a heavy underdog—the odds ran anywhere 11–1 to 25–1 in Mayweather's favor—so if he manages to go the distance or even win against the much more experienced boxer, Vegas could stand to lose a lot of money. White had said a 50–50 split of the pot would be 'pretty fair,' although the ultimate financial agreement remains to be seen.