Floyd Mayweather caught everyone by surprise on Monday by announcing a lucrative upcoming fight against Tenshin Nasukawa.

The former five-weight world champion, who turns 42 in February, was expected to fight again in the near future - but not against a 20-year-old kickboxer.

Speculation has been rife in recent weeks that Mayweather would take on either Conor McGregor or Manny Pacquiao again - the American has beaten both fighters in the past three years - while there were also rumours that he could go head-to-head against UFC star Khabib Nurmagomedov.

Instead, Mayweather will take on Nasukawa, who has a 27-0 record in kickboxing and a 4-0 record in MMA, on December 31 in Japan.

"I wanted to do something different," Mayweather told reporters, per BBC Sport, during the announcement. "I wanted to display my skills outside the US and be in a special fight. I want to give the people what they want - blood, sweat and tears."

Mayweather is expected to earn a figure in the region of $88 million for next month’s fight and, in the process, will take his career earnings over the $1 billion mark.

However, rap star 50 Cent is clearly unimpressed by the match-up judging by his latest Instagram posts.

Fiddy, who has made headlines in the past for his controversial social media posts related to big fights, posted: “Champ fighting a Uber driver before the IRS embarrass him again. Pay-per-view my ass, we watching this on YouTube.”

Ouch. He’s made his feelings about the upcoming fight crystal clear.

TMZ report that 50 Cent wanted to see Mayweather fight Gennady Golovkin, adding: "What happen to GGG, couldn't find his phone number. get the f**k outta here wit this sh*t."

He also wrote: "Champ done turned into a circus act ... at least Canelo fighting killers."

50 Cent was on Mayweather’s side when the legendary boxer fought McGregor in 2017, so what’s happened between them?

TMZ claim the pair have been “beefing on social media for months now”, with Mayweather recently explaining that a rift between his manager, Al Haymon, and the rapper started the feud.

Either way, 50 Cent is far from the only fight fan who feels this way about Mayweather’s latest announcement.