Floyd Mayweather reveals how close he was to fighting Conor McGregor

A fight between Floyd Mayweather (L) and Conor McGregor (R) could happen. Photos / Getty

Floyd Mayweather Jnr says he almost came out of retirement to fight UFC featherweight champion Conor McGregor.

Mayweather Jnr, 39, retired from boxing in September 2015 but was recently considering a bout with McGregor.

"I tried to make the fight happen between me and Conor McGregor," Mayweather Jnr told FightHype.com.

"We weren't able to make the fight happen, so we must move on."

The American added: "I feel honoured to be the biggest name in MMA and in boxing, and I don't even compete no more."

Last month McGregor said he was interested in fighting the former five-division world champion as long as Mayweather could come up with the appropriate funds for the crossover fight.

"Right now, I have Floyd running around the Showtime [Network] offices gathering my money. That's what he's doing," the Irishman said on August 15.

"He's running around the Showtime offices, begging those executives to come up with the $US100 million cash he needs to fight me. As soon as he gets my money, we can fight."

McGregor, 28, is under contract with the UFC, and any potential fight against Mayweather Jnr would have had to involve a co-promotion or the UFC's blessing.