Floyd Mayweather isn't making as much money as he says he is for fighting Mikuru Asakura.

That is according to MMA veteran Chael Sonnen, who questioned the boxing legend's bold claim that he will earn around £18 million for his exhibition bout with Asakura.

Money, 45, takes on the Japanese MMA fighter on September 25, having recently gone the distance against YouTube star Logan Paul and former sparring partner 'Dangerous' Don Moore.

The fight will take place at the Super Arena in Saitama, Japan, as part of RIZIN 38. It will not count towards his overall professional record.

ALL THE INFO: Floyd Mayweather vs Mikuru Asakura: Date, Card, UK Start Time and more

However, former Bellator and UFC fighter Sonnen suggested that the real figure he earns will actually be less than half of that number somewhere in the region of £7 million.

Chael Sonnen disputes Floyd Mayweather's claims about his exhibition bout with Mikuru Asakura

Floyd Mayweather vs Mikuru Asakura Fight Card

Image Copyright: RIZIN

“Floyd is claiming he’s gonna get $20 million for this - I call it ‘rassling because they’re not actually [fighting] - but whatever they’re getting ready to do in Japan, whatever that is that’s going to look like boxing, he’s getting $8 million,” he told his YouTube channel. “Now, eight is a beautiful number.

"But he claimed he was getting 20. So I feel because I know the real number, that I can’t let it go. I must come to you guys.

"I have a journalistic obligation to come and inform you it’s actually $8 million and he’s exaggerating.

“He going to do something - exhibition? They’re calling it something. He’s doing ‘little guys that are terrible.’

"He’s getting good exposure making a bunch of money and he’s having a really good time. All of those things bother me. I don’t want him having a good time.

"No fighter gets to have fun. No fighter that’s 40 years old that isn’t doing actual fights, only pretending to go against terrible competition that can barely sell.

"I mean these guys can barely even pretend that they’re knocked out. It’s not all that good. They don’t get to have fun and make millions of dollars.”

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Chael Sonnen claims Floyd Mayweather is faking his fights

Since his retirement in 2017, Mayweather has guest-starred in movies and music videos and moved into motorsport by launching his own NASCAR racing team.

Asakura, meanwhile, has spent his entire career competing in mixed martial arts.

And Sonnen believes the whole thing is staged anyway as he insists there is no way he would be able to stand with him in the ring otherwise.

“Floyd’s going to go make $8 million to not actually compete with a guy who if he did compete with he would destroy in 30 seconds,” he added. “Other people that are actually willing to fight, not call it an exhibition, not go out for eight rounds, not shorten the time limits to two a piece instead of three can’t make a 10th of that.

"Why would I tease Floyd? Doesn’t it sound like Floyd’s the one that figured it out?

“If Floyd can go in there and get $8 million for whatever that is and he doesn’t have to work very hard, he doesn’t have to train at all because the script is on his side and they’ve already told him who’s going down and when, isn’t that something I’d want to emulate?

"Floyd’s gonna go over to Dubai, he’s gonna do something after this, which will represent the second time that he’s done that, and he’s going to get millions of dollars. I don’t know, I think in Dubai, they’re actual competition, they’re just with bums. Those might also be scripted like the stuff he’s doing in Japan, I don’t actually know that, I haven’t got to see one, they’re like little private events.”