Bellator is getting into the superfight business.

The promotion has booked a fight between middleweight champion Gegard Mousasi and welterweight champion Rory MacDonald on Sept. 29 in San Jose, Calif., multiple sources confirmed to ESPN.

Bellator middleweight champion Gegard Mousasi will put his 185-pound belt on the line Sept. 29 when he faces welterweight champion Rory MacDonald in San Jose. Per Haljestam/USA TODAY Sports

The fight will be contested at 185 pounds and Mousasi's middleweight title will be on the line. Should MacDonald win, he'd be the first fighter in Bellator history to hold two belts at the same time. The fight, which features two former UFC contenders, is arguably the biggest in Bellator's history.

Mousasi (44-6-2) won the title in May at Bellator 200 when he defeated Rafael Carvalho via first-round TKO. The MMA veteran has won his last seven fights in a row.

MacDonald (20-4) became Bellator's 170-pound champion when he defeated Douglas Lima in January.

Also slated for the card will be Quinton Jackson vs. Wanderlei Silva 4, sources confirmed to ESPN. Silva will head into the fight with a 2-1 record against "Rampage."