Floyd Mayweather Jr. has never stepped inside the octagon for a sanctioned bout, but the retired boxer claims he is the biggest thing going in mixed martial arts.

Mayweather claims he will come out of retirement to fight the guy who is currently recognised as MMA's top star, Conor McGregor.

So far, it has been a lot of talk - including a $15million offer from Mayweather to McGregor.

"I'm not just the face of boxing, I'm the face of mixed martial arts also. And I'm not an MMA fighter, but I do support all contact sports," Mayweather said during a Facebook Live interview via ESPN Boxing.

"I haven't seen an MMA fight in a while, but anytime I see an MMA fighter that wants to take a picture with me, I'm gonna take a picture with them because they go through a lot.

"Fighters go through a lot to get to a certain level and MMA fighters go through a lot just like boxers go through a lot."

As for an actual fight between Mayweather and McGregor inside an octagon or ring, it has been just a lot of noise so far.