Mayweather will move up in weight for the fight, which will be for De La Hoya's 154-pound title and will be held next May 5 either in Las Vegas or Los Angeles.

De La Hoya previously said the fight would be the last in a pro career that began after he was the only U.S. boxer to win a gold medal in the 1992 Olympics. He's the biggest box office draw in boxing, though he has fought only sporadically in recent years.

Mayweather is generally regarded as the best pound-for-pound fighter in the sport, and is coming off a near shutout win over Carlos Baldomir on Nov. 4 for the 147-pound title. Though Mayweather dominated the bout, he was criticized for not trying to knock Baldomir out.

Following that fight, De La Hoya gave Mayweather a week to come to terms if he wanted to fight him. Terms of the agreement weren't disclosed.

Richard Schaefer, the CEO of De La Hoya's Golden Boy Promotions, said the fight has the potential to set records for pay-per-view sales. The previous record was set when 1.99 million customers bought the second Evander Holyfield-Mike Tyson heavyweight title fight in 1997.