London - Floyd Mayweather Jr said Saturday a fight against UFC champion Conor McGregor is "90 percent" likely - if he boxes again.
The retired undefeated five-weight world champion, who has not boxed since September 2015, admits he wants to fight Irishman McGregor rather than any boxer in a clash that would attract global interest and could set new records for pay-per-view revenue.
UFC lightweight champion McGregor, 28, last week applied for a boxing licence in Nevada and there has been mounting speculation the pair will meet in the boxing ring this year.
American Mayweather, 40, broke his silence on ending his retirement and trying to extend his perfect record to 50-0 against McGregor, who has a UFC record of 21 wins and three defeats.
"If I do fight, there's a 90 per cent chance it's against Conor McGregor," Mayweather told a news conference on Saturday night at the Copper Box Arena in London.
"The only sort of numbers I worry about are pay-per-view numbers. I have to see what the next move is."
Critics have claimed it would be a mismatch, but Mayweather insists it is the biggest fight to be made in boxing and mixed martial arts.
"The only fight that makes sense to me is the McGregor fight," Mayweather said.
"I've accomplished everything (else) I want to accomplish. Conor McGregor is professional and so am I. He's a stand-up fighter and I'm a stand-up fighter. He kicks ass in the octagon and I kick ass in the boxing ring.
"The fans demand that fight and you have to give the fans what they want to see."
Mayweather, who was sport's biggest earner before he retired following his win over Andre Berto in September 2015, will discuss fighting McGregor with his advisor Al Haymon when he returns to America next week.
"I'm over here right now, working, always working," said Mayweather, who out-pointed Manny Pacquiao in boxing's richest fight in Las Vegas in May 2015.
"When I get back to the US I will call Al [Haymon] and see what our next move is, there's no rush. I have to put my team together.
"Most likely when we do make the move it's going to be a very huge move. When Floyd Mayweather fights, it's history.
"The only thing I'm chasing right now is my own record. When the times comes I will get the team together."