Top five middleweights Jacare and Gastelum meet in Rio

Two of the top middleweights in the world will meet at Jeunesse Arena in Rio de Janeiro, Brazil on May 12, as No. 2-ranked Ronaldo "Jacare" Souza battles No. 5-ranked Kelvin Gastelum in a pivotal UFC 224 matchup.

Already announced for the UFC 224 event, which airs live on Pay-Per-View, is a clash of Brazilian superstars, as Vitor Belfort makes his final walk to the Octagon to face Lyoto Machida.

Fresh from a first round knockout of Derek Brunson in January that earned him his fifth post-fight performance bonus in the Octagon, former Strikeforce champion Souza will fight in Brazil for the first time in two years on May 12 as he looks to make a case for a world title shot against the equally ambitious Gastelum, a former Ultimate Fighter winner who scored Performance of the Night honors in his last fight, a stunning first round knockout of Michael Bisping in November.