RIZIN’s annual New Year’s Eve just became bigger than ever before. It was announced late Monday at noon in Japan (Sunday night in the west) that undefeated boxer Floyd Mayweather will face undefeated kickboxer Tenshin Nasukawa. The exact ruleset hasn’t been made clear as of yet, but at the press conference, which both fighters were present at, Mayweather said that it will be announced in the “coming weeks.”

In mid-September articles said that Mayweather expressed interest in fighting in Japan in what would be a tune-up fight before fighting Manny Pacquiao in a sequel matchup. Less than an hour before the press conference had went live, Mayweather teased his partnership with RIZIN by posting an Instagram photo where he wore a RIZIN MMA glove in his left hand and their kickboxing/boxing glove in the other hand.

Both fighters’ last appearances were in crossover events, with Mayweather participating in the highly lucrative boxing bout with MMA star Conor McGregor. In RIZIN’s promotion Tenshin recently battled MMA star in his own right, Kyoji Horiguchi in a kickboxing bout at RIZIN 13.

RIZIN 14 is scheduled to take place on New Year’s Eve at Saitama Super Arena, the unofficial home for RIZIN events. The rest of the card is set to be announced later this week.