Floyd Mayweather will celebrate a surprise comeback against 20-year-old Japanese kickboxing sensation Tenshin Nasukawa at Saitama Super Arena just outside of Tokyo on New Year's Eve – whether it's a boxing, kickboxing or mixed martial arts fight is not yet known.
Mayweather, the story's most profitable boxer, can expect to bring more than $ 100 million to the competition.
The American earned more than $ 240 million in the fight against UFC star Conor McGregor 17 months ago in Las Vegas and was involved in four of the five biggest competitions in martial arts history.
Mayweather and Nasukawa were shown overnight at a Tokyo press conference, which was streamed worldwide on YouTube and hosted by the Rizin Fighting Federation, a Japanese fighting company that promotes MMA and kickboxing events.
Mayweather, undefeated in 50 fights and champion in five box-weight divisions, said the rules of the fight are not yet clear.
"As far as the weight class and the rules are concerned, we'll talk about it," Mayweather said, insisting it was "special" because "we're giving people something they've never seen before."