Floyd Mayweather has won world titles in five different weight classes and is 50-0 in an unparalleled boxing career, but after signing with the Japanese organizer RIZIN Fighting Federation, he could provide a change in the rules for a breathtaking detour.
The undefeated 41-year-old, who said last year that his boxing career was over after stopping UFC superstar Conor McGregor, said he could keep up with the format agreed for the New Year's Eve fixture in Saitama.
His opponent is 20-year-old Japanese kickboxer Tenshin Nasukawa.
Mayweather never fought professionally under the MMA rules and did not specify in which format the fight would follow. He said negotiations were underway with Nasukawa's representatives and that his skills would not end in boxing.
"I can wrestle, I can wrestle a bit, I can box a lot," Mayweather told Reuters.
"We'll just see it, I can do anything, I can do anything if I'm ready."
Nasukawa is under contract with RIZIN and denies her championships in the MMA field as well as in pure kickboxing. He has won all four of his MMA bouts.
While boxing rules restrict fights to the use of fists, MMA rules may include kicks, knees and elbow strikes, as well as wrestling, joint locks, and chokes.
Mayweather was confident that they would make an agreement that would suit both fighters.
"I'm pretty sure that when I talk to the guys from my team, we'll come to the same page so we can go out there and do what we need to do," he added.
Mayweather had said in September that he would be retiring for another fight with Manny Pacquiao after the two of them were spoken at a music festival in Japan.