Just a few weeks after his victory over Robert Guerrero, Floyd Mayweather’s next fight has already been scheduled.

The 36-year-old will take on Saul “Canelo” Alvarez on Sept. 14. Mayweather announced the news on Twitter on Wednesday night, saying he is “giving the fans what they want.” The fight will take place at the MGM Grand.

According to The Las Vegas Review-Journal, the boxers will compete at a catch weight of 152 pounds. Against Guerrero, Mayweather came in at 146 pounds. On April 20 against Austin Trout, Alvarez weighed in at 153.5 pounds. Mayweather’s junior middleweight and welterweight world titles, as well as Alvarez’s WBC and WBA super welterweight belts, will be on the line.

Mayweather is considered the best pound-for-pounder boxer, but this may be his most difficult challenge in quite some time. It’s the first time he will step into the ring with another undefeated fighter, since he fought Ricky Hatton in 2007. At just 22 years old, Alvarez has compiled a record of 42-0-1.

The betting odds favor Mayweather, but not as much as they have in recent bouts. The online betting Web site Bovada.lv has set the early odds at Mayweather-280 and Alvarez+220. In his previous three bouts against Guerrero, Miguel Cotto and Victor Ortiz, Mayweather was a -750, -700 and -625 favorite.

Despite having to face an undefeated boxer that is 14 years his junior, Mayweather and his camp are supremely confident. Mayweather’s co-manager, Leonard Ellerbe, says his client won’t have any problems with moving up a weight class.

“Canelo can come in at 200 pounds if he wants to; he’ll still get his butt whipped,” Ellerbe said. “Floyd is the best athlete in sports. He won’t have any problems with 152 pounds.”

Alvarez has been able to amass such an impressive record at a young age by taking on a lot of inferior competition. However, he has taken down a few big names in his time as a professional. He’s defeated the likes of Trout, who was coming off a strong win against Cotto, Shane Mosely and Josesito Lopez.

In his May 5 fight against Guerrero, Mayweather was guaranteed $32 million. The Sept.14 matchup will be the second of a six-fight contract with Showtime that could pay him upwards of $200 million. According to Forbes, Mayweather’s next fight could land him a record $50 million payday.

The bout between Timothy Bradley and Juan Manuel Marquez, which was originally scheduled for Sept.14, has now been moved to Oct.12. The two boxers will face off after each picked up a victory against Manny Pacquiao.