For what is dubbed to be Floyd Mayweather Jr.'s last fight before he retires, the undefeated American boxer will go against Haitian-American boxer Andre Berto as officially announced on Tuesday.

Four months after his win against Filipino boxer Manny Pacquiao, ESPN said Mayweather will go against Berto on Sept. 12 at the MGM Grand in Las Vegas.

Mayweather has reportedly stressed that the fight, which will be shown on Showtime at 8 p.m. ET, will be the last in his career as a boxer as he eyes a 49-0 record.

"I'm ready to get back in the ring on Sept. 12 and prove again to the whole world why I'm the best ever. I always bring my A-game, and this fight against Andre Berto is no exception. He's a young, strong fighter who is hungry to take down the best. Forty-eight have tried before, and on Sept. 12, I'm going to make it 49," Mayweather said.

According to the BBC, Mayweather seemed to have chosen a less powerful opponent in Berto, who has reportedly "lost three of his last six fights, with him suffering reverses to Victor Ortiz and Robert Guerro - both of whom have also been beaten by Mayweather - as well as Jesus Soto."

Mayweather is confident that he can outclass Berto during their match. According to Sports Illustrated, he will once again "get what he wants."

"He will pocket another win, collect another $30 million or so and burnish the self propelled narrative that he is invincible," the same report said.

With a 30-3 record inclusive of 23 knockout victories, Berto is a current welterweight world titleholder.

Despite being the underdog, Berto said that he still plans to stain Mayweather's undefeated record.

"I'm coming to kick Floyd's ass on Sept. 12. Best believe that I plan to bring it to Floyd and I'm not concerned about what 48 other fighters have been unable to do. Somebody is getting knocked out, and it won't be me. You don't want to miss this," Berto confidently said.

More details of the upcoming bout will reportedly be discussed during a news conference on Thursday in Los Angeles at 3 p.m. though the event is closed to the public.