Floyd Mayweather is coming out of retirement. The former boxing champion, retired from ring combat following an August 2017 boxing match against UFC star Conor McGregor, will be participating in a Japanese mixed martial arts (MMA) contest on New Year’s Eve, according to details released during a news conference in Tokyo on Monday.Mayweather, who left boxing with a perfect 50-0 record, is set to get in the ring with kickboxing champion Tenshin Nasukawa on Dec. 31 at the Saitama Super Arena in Saitama, Japan.

It wasn’t immediately clear if the bout would be a boxing match, a mixed martial arts contest, or some mix of both, although Mayweather did post an image to social media in which he sported a pair of Rizin gloves.

The Rizin Fighting Federation, a Japanese MMA organization created in 2015, will put on the fight.

Other specifics of the fight, including the weight class and the set amount of rounds, were not announced.

“As far as the weight class and the rules, we’ll talk about that,” Mayweather said, according to ESPN. “We’ll get that situated within the next couple of weeks. This particular bout is a special bout as far as we’re giving the people something they’ve never seen before. The world has never seen Mayweather compete live in Tokyo. Throughout the years, I’ve seen a lot of fans from Japan come to Las Vegas and come to the U.S., but me and my team said, let’s do something different. Let’s go over to Japan.”

Mayweather recently had discussed a potential rematch with Manny Pacquiao for the New Year’s Eve date. But Pacquiao is now heading toward a separate fight in January, meaning a potential rematch between the two fighters – who combined for the richest fight in boxing history in 2015 – could be pushed to the spring.