Floyd Mayweather has announced a sensational return to the ring next year with an Instagram post declaring: 'Coming out of retirement in 2020'.
Mayweather's post was then reposted on Twitter by UFC president Dana White, after speculation in recent days the two were planning to work together.
The announcement by Mayweather will also fuel speculation he could be about to make the move into UFC.
He has previously suggested he would one day move into mixed martial arts in some capacity, although he has also said that boxing will always reign supreme over other combat sports.
Mayweather and White were seen taking in a basketball game together on Wednesday night, sending the rumour mill into overdrive.
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Boston Celtics fan White watched his side lose 107-104 to the Los Angeles Clippers from the best seats in the house.
White had planned to launch his new venture Zuffa Boxing last month as he deviates from mixed martial arts.
He has given little away about his venture but is believed to be planning not to recognise the traditional sanctioning bodies, the IBF, WBC, WBA and WBO.
That would bring his promotion in line with the UFC which has only one belt per division.
Mayweather worked with White for his fight with Conor McGregor in 2017 which the boxer won by the 10th-round stoppage.
The 42-year-old said that when he boxed McGregor, it gave mixed martial arts a huge boost.
"We gave the MMA sport a boost," he said. "Eventually I will move on to build my brand in MMA but for right now I'm in boxing, and boxing will always be at the top as long as I'm involved."
The 42-year-old recently insisted he will not return to the ring despite being linked with a rematch with Manny Pacquiao.
"I've got calls to get back into the ring, but my health is my wealth," he told Reuters.
"Boxing is a very, very brutal sport. In the last few years a lot of fighters have died inside that squared circle.
"You have got to know when to hang it up. I had a great career.
"I'll still travel and do exhibitions. I make great money doing exhibitions; between $10 and $30 million.
"I think I make more doing that than most fighters make fighting."
But he appears to have performed a U-turn with his latest announcement.