MMA figher Connor Mcgregor arrives onstage holding the Irish National flag for the weigh-in with boxer Floyd Mayweather Jr. (out of frame) on August 25, 2017 at the T-Mobile Arena in Las Vegas, Nevada.
Mayweather, the 40-year-old undefeated former welterweight boxing champion, has been lured out of retirement to face McGregor, a star of mixed martial arts' Ultimate Fighting Championship. The two men meet in a 12-round contest under boxing rules on August 26th that is tipped to become the richest fight in history. / AFP PHOTO / John GURZINSKI        (Photo credit should read JOHN GURZINSKI/AFP/Getty Images)