Floyd Mayweather Backs Out of Japan Fight with Tenshin Nasukawa

12:24 PM PT -- Floyd had already made up his mind to back out of the fight by Tuesday night -- because he was telling people at an L.A. nightclub that it was off.

In fact, Floyd's friend Michael Blackson -- the famous comedian -- came on "TMZ Live" on Wednesday and told us when he saw Floyd at Murano Nightclub, the boxer made it clear it wasn't happening.

Floyd Mayweather is making it clear his massive New Year's Eve fight with Tenshin Nasukawa is off -- and claims it's because he was misled by fight promoters.

It's strange considering the press conference Floyd participated in on Sunday night -- promoting the fight at RIZIN 14 in Japan -- but alas, here we are.

In short, Floyd claims he only ever agreed to fight Tenshin in a private, closed door, 3-round exhibition fight "for a small group of wealthy spectators for a very large fee."

But, when he got to the press conference (weird that he would even agree to do a press conference for a small private event) the RIZIN promoters told the media it would be a globally televised superfight.

Floyd says he went along with the press conference because he was blindsided and didn't want to "create a disturbance."

During the press conference, Floyd was PRAISING the fight promoters and said the goal was to create a longterm relationship with RIZIN to promote more fights together in the future.

Whatever the case, seems the fight's off for good. Here's Floyd's statement in its entirety.

"Now that I am back on U.S. soil after a long and disappointing trip to Tokyo, I now have the time to address you, my fans and the media in regards to the upcoming event on December 31st that was recently announced."

"First and foremost, I want it to be clear that I, Floyd Mayweather, never agreed to an official bout with Tenshin Nasukawa. In fact (with all due respect) I have never heard of him until this recent trip to Japan. Ultimately, I was asked to participate in a 9 minute exhibition of 3 rounds with an opponent selected by the 'Rizen Fighting Federation.'"

"What I was originally informed of by Brent Johnson of 'One Entertainment' was that this was to be an exhibition put on for a small group of wealthy spectators for a very large fee. This exhibition was previously arranged as a "Special Bout" purely for entertainment purposes with no intentions of being represented as an official fight card nor televised worldwide."

"Once I arrived to the press conference, my team and I were completely derailed by the new direction this event was going and we should have put a stop to it immediately."

"I want to sincerely apologize to my fans for the very misleading information that was announced during this press conference and I can assure you that I too was completely blindsided by the arrangements that were being made without my consent nor approval."

"For the sake of the several fans and attendees that flew in from all parts of the world to attend this past press conference, I was hesitant to create a huge disturbance by combating what was being said and for that I am truly sorry."

"I am a retired boxer that earns an unprecedented amount of money, globally, for appearances, speaking engagements and occasional small exhibitions."