Boxing star Floyd Mayweather said Wednesday he never agreed to fight a New Year's Eve bout against unbeaten 20-year-old Japanese mixed martial arts fighter Tenshin Nasukawa and insists he was misled by local organizers.

Three days after Mayweather appeared at a news conference in Japan to announce the Rizin Fighting Federation bout at Saitama Super Arena, the 41-year-old explained in an Instagram post why he is scrapping the planned fight.

"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," the American, who was unbeaten in 50 professional fights, wrote.

"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."

Despite posting on Instagram on Sept. 15 that he is "coming back to fight Manny Pacquiao this year," Mayweather also reiterated that he is retired from competitive boxing.

He said he was made to believe the Nasukawa fight would be an "exhibition put on for a small group of wealthy spectators for a very large fee."

In the press conference held Monday, no details of the aborted year-end bout were disclosed, and Mayweather said in his Instagram post that he had "never heard of Nasukawa until this recent trip."

A public relations representative from the Japanese MMA promotion company Rizin said, "We are now confirming (Mayweather's) intention and will inform you as soon as we know."