Former world boxing champion Floyd Mayweather will fight UFC champion Conor McGregor in a boxing match in Las Vegas on 26 August.

American Mayweather, 40, posted a video on Twitter confirming the details of the contest with the message: “It’s official.”

Irish UFC lightweight champion McGregor, 28, said “the fight is on”.

Former five-weight world champion Mayweather retired unbeaten in September 2015 after 49 bouts.