After defeating Filipino pugilist, Manny Pacquiao on Saturday, Floyd Mayweather Jr. is moving on with another fight. This time, it's not going to happen inside the ring but inside a courtroom.

The American professional boxer, who brought home $180 million after his victory during the "Fight of the Century," is reportedly facing a $20 million defamation lawsuit.

The lawsuit was filed by Josie Harries, the same person he was convicted of assaulting back in 2012, TMZ has learned.

According to the lawsuit, Harris, who has three kids with Mayweather, has decided to sue the champ after the latter denied beating her up during an interview with Katie Couric, which aired on TV about two weeks ago.

Harris claims Mayweather's statement was the prime reason why she is now facing "large scale humiliation" by being labeled a drug addict.

It can be noted that Mayweather had served two months in prison due to the assault. However, during his interview, the undefeated boxer maintained that he did nothing wrong. noting that he only subdued his ex-partner because she was under the influence of drugs.

"Did I kick, stomp and beat someone? No, that didn't happen," Mayweather told Couric at the time. "I look in your face and say, 'No, that didn't happen.'"

"Did I restrain a woman that was on drugs? Yes, I did. So if they say that's domestic violence, then, you know what? I'm guilty. I'm guilty of restraining someone," Mayweather added.

Harris, who is suing Mayweather for $20 million, gushed about her relationship with the pugilist to USA Today Sports in 2014. 

"I was a battered woman. I felt embarrassed about saying I was a battered woman," Harris said at the time.  

"I felt shame. I felt like it was my fault. What did I do? I didn't understand what a battered woman was at that time," she continued. "Now I know I was in a very dysfunctional, hostile relationship and a victim of domestic violence."

Mayweather has yet to comment on Harris' lawsuit against him.