Boxing's best pound-for-pound fighter, welterweight/junior middleweight champion Floyd Mayweather Jr. returns to action Sept. 13 for a title rematch with Marcos Maidana. Mayweather announced the fight Thursday on the photo-sharing app Shots.

He later confirmed the bout on Twitter.

The fight, which is being billed as 'Mayhem II,' will be held at MGM Grand Garden Arena in Las Vegas. It will air on Showtime pay-per-view, and is the fourth of a six-fight deal Mayweather has with the cable network. Mayweather [46-0-0, 26 knockouts] will hold his 10th fight in a row at MGM Grand.

He recently acquired a promoter's license in New York, leading to speculation that his September bout might take place at Barclays Center in Brooklyn.

In his first meeting with Maidana on May 3, Mayweather chose to fight in close quarters for much of the bout and escaped with a majority decision. While most ringside observers had Mayweather winning, it was the second straight fight in which one official judge scored the bout a draw.

Saul 'Canelo' Alvarez was on the short end of a majority decision against Mayweather in their September 2013 junior middleweight title fight. As was the case with Maidana, most ringside observers had Mayweather winning the fight.

Mayweather-Alvarez registered 2.2 million pay-per-view buys, the second highest in boxing history. Mayweather, currently the world's highest-paid professional athlete, also holds the record for boxing's highest selling pay-per-view bout -- 2.5 million buys -- which he recorded in May 2007 against Oscar De La Hoya.

Despite his previous impressive pay-per-view numbers, the first bout with Maidana was disappointing by Mayweather standards. That fight reportedly drew around 990,000 pay-per-view buys.

The hard-hitting Maidana will bring a professional record of 35-4-0 (31 KOs) into the rematch. He earned the first fight against Mayweather with an impressive unanimous decision in December 2013 over then-unbeaten and WBA welterweight titleholder Adrien Broner.

According to Yahoo! Sports, Mayweather-Maidana II will be co-promoted by Golden Boy Promotions and Mayweather Promotions. Mayweather had vowed not to do any more fights with Golden Boy Promotions after CEO Richard Schaefer left the company in June.