The big stumbling block for Mayweather, who has the nickname money, is funnily enough money. The five-division world champion who has a 49-0 record has previously stated that he'd want US$100m to fight McGregor.
UFC boss Dana White, who owns the promotional rights to McGregor, has previously offered Mayweather $25m for the fight. In return Mayweather called White a "f**king comedian".
A source close to the McGregor camp reportedly told the Irish Sun that the deal for what would be the biggest fight in history has been struck.
"The contract hasn't officially been signed yet because of a third party holdup but all details have been agreed on," the source said.
"The fight could even be announced within two weeks."
Despite the fact it would be McGregor's professional boxing debut, Mayweather still backed the UFC star to put up a fight.
"I mean cause every time Conor McGregor goes out there and compete and win, he do it standing up," Mayweather said.
"When Conor McGregor did lose, he lost on the ground. He didn't lose standing up. So he's a hell of a fighter and a very, very tough competitor and he has the will to win.
"The UFC gloves is no different from boxing gloves, they just a little bit smaller but if a guy got power, he got power and Conor McGregor got power."