Floyd Mayweather Jr. (L) of the U.S. and UFC lightweight champion Conor McGregor of Ireland pose during a news conference in Las Vegas

File Photo: Floyd Mayweather Jr. (L) of the U.S. and UFC lightweight champion Conor McGregor of Ireland pose during a news conference in Las Vegas, Nevada U.S. on August 23, 2017. REUTERS/Las Vegas Sun/Steve Marcus