Boxing: Floyd Mayweather says he's 'coming out of retirement' in Instagram post

Boxing legend Floyd Mayweather says he is coming out of retirement.

The 42-year-old American has not fought since the 50th fight and 50th win of his career in August 2017 - his victory over UFC star Conor McGregor, fought under boxing rules.

A rematch, possibly under UFC rules, has long been touted, as have traditional ring returns against several opponents.

In an Instagram post, Mayweather - a five-weight world champion - simply said: "Coming out of retirement in 2020."

Hinting his claimed return would be something more than a boxing one, he posted another picture with UFC boss Dana White, who helped promote the McGregor fight, saying the pair were "working together again".

They sat next to each other in the front row of Thursday's Boston Celtics v LA Clippers NBA game in Los Angeles.

AAP