Japan promoter says Mayweather bout with kickboxer back on

An unprecedented match-up between boxing superstar Floyd Mayweather Jr and a Japanese kickboxer half his age is back on, according to the Japanese promoter behind the fight.

The bout between Mayweather and Tenshin Nasukawa, first announced earlier this month, was abruptly scrapped by the American boxer shortly after he revealed his plans to take on the kickboxer.

But on Friday, the CEO of mixed martial arts promotor RIZIN said the fight planned for New Year's Eve was back on.

"Misunderstanding with Floyd Mayweather has been resolved," Nobuyuki Sakakibara tweeted on his account.

"He will face off against Tenshin Nasukawa on December 31, New Year's Eve."

"I will talk about the details at a press conference when I return to Japan," he added, alongside a picture of himself, Mayweather, and a third man.

The tweet comes after Mayweather told the US website TMZ Sports on Wednesday in California that the fight would go ahead.

"We're going to make it happen," he reportedly told the site.

"It's a no-brainer."

When the fight was first announced, it was unclear what rules would govern the match-up between the retired welterweight boxer and Nasukawa, an unbeaten kickboxer.

But Mayweather told TMZ Sport the face-off would involve "no kicking."

"Rules? It's going to be a little boxing exhibition," he said.

"I'm moving around with the guy for nine minutes, and of course it's going be the highest paid exhibition ever," he added.

The unbeaten 41-year-old, who won world titles in five different weight divisions, made headlines earlier this month when he announced on his Instagram page that he was coming out of retirement for the fight.

"I want to give the people what they want -- blood, sweat and tears," he told a news conference in Tokyo afterwards.

But just two days later he posted a lengthy statement on his social media accounts saying he had been "blindsided" by organisers of the bout and had "never agreed" to the fight.