Francis Ngannou will face Renan Ferreira on his return to MMA on 19 October.
The Cameroonian heavyweight will make his promotional debut for the Professional Fighters League (PFL), having previously been a UFC champion.
On the undercard, long-time Bellator featherweight champion Cris Cyborg will face PFL two-weight champion Larissa Pacheco.
Winners of both contests will receive the PFL’s newly established “super-fights championship belt.”
Ngannou, 37, has spent the past year focusing on boxing, with fights against former world champions Tyson Fury and Anthony Joshua.
Ngannou lost both bouts, suffering a second-round knockout to Joshua in March after a split-decision points loss to Fury.
Brazil’s Ferreira won the PFL’s 2023 heavyweight tournament and has been touted as Ngannou’s opponent since defeating Bellator’s heavyweight champion Ryan Bader in February.
Ferreira, 34, has 13 wins, three losses, and three no-contests on his MMA record, with eleven of his 13 wins coming via knockout.
Ngannou has 17 victories in 20 MMA fights, with his last win being a points decision over Frenchman Ciryl Gane in the UFC in January 2022.
He left the UFC at the end of his contract in 2023, citing a desire to switch to boxing.
Ngannou signed with the PFL last year and was named chairman of the PFL’s African league, which launches in 2025.
The PFL uses a league format in the United States, with British flyweight Dakota Ditcheva reaching the final of the 2024 tournament.
Ngannou’s fight against Ferreira will be a one-off, with the Brazilian deciding against entering the 2024 heavyweight tournament as he awaited a bout with Ngannou.