Japanese kickboxer Tenshin Nasukawa has vowed to "take down" boxing legend Floyd Mayweather in their three-round exhibition match in Japan on Monday.
Former five-weight world champion Mayweather, 41, will come out of retirement to fight Nasukawa over three rounds of boxing in Saitama.
Nasukawa competes in the RIZIN Fighting Federation in both kickboxing and mixed martial arts.
"People in Japan, listen. I will take down Mayweather," said the 20-year-old.
"You should look forward to it."
Speaking at a news conference, Mayweather, who beat UFC's Conor McGregor in a boxing match in August 2017, promised to "entertain".
Monday's fight will follow boxing rules and consist of three, three-minute rounds, with Nasukawa forbidden from kicking.
Both Mayweather and Nasukawa are undefeated in their respective sports but neither's perfect record will be on the line because of the exhibition nature of the bout.