Bellator officials announced the bout on Tuesday.
After winning season nine's lightweight tournament, Brooks (13-1) is expected to challenge the winner of Bellator 102's main event, Eddie Alvarez vs. Michael Chandler III. In the interim, though, he'll fight Bellator newcomer Jolly (13-5).
"I'm so happy to be getting back in that cage," Brooks said in a statement. "I would be lying if I said I didn't have my sights set on Alvarez vs. Chandler III, just like everyone else, but at the same time I know how focused I am for this next fight. I'm really looking at this fight as more of a blessing than anything else."
Brooks, 27, has compiled a 5-1 record inside the Bellator cage since debuting with the promotion in early 2013. After falling short in season eight's tournament, Brooks wrestled his way to a trio of unanimous decision wins over John Alessio, Saad Awad and Alexander Sarnavskiy to claim season nine's tourney crown.
"What some people don't understand is when you get into that tournament, you are doing everything you can to get through it healthy and keep racking up those wins," Brooks said. "My coaches and I came in with a game plan for the tournament, and while it obviously paid off, I know there are so many adjustments I still want to make to my game, and I want to show my fans the sort of skills I have. With a full training camp under my belt, I know I'm going to take my game to the next level and really show fans how my game has evolved."
Jolly, 31, makes his Bellator debut having won three of his last four fights, including a recent unanimous decision over Gerric Hayes at XFC 26.
"I'm coming into this fight with really nothing to lose," Jolly said. "I'm pumped to be able to fight for Bellator on such a big stage and against a guy that I feel I match up very well against."
Bellator 120 takes place May 17, 2014 at the Landers Center in Southaven, MS. An updated fight card can be seen below.
- Eddie Alvarez vs. Michael Chandler
- Rampage Jackson vs. Muhammed Lawal
- Will Brooks vs. Nate Jolly