It will be Boxing rather than MMA.
Floyd Mayweather to fight Conor McGregor in boxing match in August
Conor McGregor has previously tweeted this mocked-up picture of the two fighters
Former boxing world 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 with the message: "It's official."
Irish UFC lightweight champion McGregor, 28, said: "The fight is on."
It is reported that each fighter could earn $100m (£78.4m) from the bout, which would be one of the richest in boxing history.
Former five-weight world champion Mayweather, widely considered the best boxer of his generation, retired unbeaten in 2015 after 49 bouts.
It followed a successful defence of his WBC and WBA welterweight titles, a victory that equalled Rocky Marciano's career record of 49-0.
Mayweather retired for the first time in 2008 after 39 fights.
Mixed martial artist McGregor, who has never boxed professionally, became the UFC's first dual-division champion in November 2016 and has previously challenged Mayweather to a fight under mixed martial arts rules.
His boxing licence was granted by the California State Athletic Commission in December, allowing him to box in the US state.
You must log in or register to see media
Floyd Mayweather to fight Conor McGregor in boxing match in August
You must log in or register to see images
Conor McGregor has previously tweeted this mocked-up picture of the two fighters
Former boxing world 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 with the message: "It's official."
Irish UFC lightweight champion McGregor, 28, said: "The fight is on."
It is reported that each fighter could earn $100m (£78.4m) from the bout, which would be one of the richest in boxing history.
Former five-weight world champion Mayweather, widely considered the best boxer of his generation, retired unbeaten in 2015 after 49 bouts.
It followed a successful defence of his WBC and WBA welterweight titles, a victory that equalled Rocky Marciano's career record of 49-0.
Mayweather retired for the first time in 2008 after 39 fights.
Mixed martial artist McGregor, who has never boxed professionally, became the UFC's first dual-division champion in November 2016 and has previously challenged Mayweather to a fight under mixed martial arts rules.
His boxing licence was granted by the California State Athletic Commission in December, allowing him to box in the US state.