The first bout has been made official for UFC Fight Night 58, to be held December 20 in Barueri, Brazil.

In what looks to be the night’s main event, Lyoto “The Dragon” Machida is set to square off with C.B. Dolloway in a contest between two of the UFC’s top-ranked middleweights.

The announcement was made by Ronda Rousey via Twitter, who is currently visiting Brazil. In fact, the UFC Women’s Bantamweight champion spent yesterday in Sao Paolo, not far from the site of UFC Fight Night 51:

Machida (21-5) is coming off a grueling five round decision loss against Chris Weidman, in an unsuccessful bid to win the UFC Middleweight Title. The former UFC Light Heavyweight Champion won his other two middleweight contests impressively. At the 185 lb limit, he has earned “Fight of the Night” honors twice, and “Knockout of the Night” honors once.

Dolloway (15-5) has won four of his last five bouts, including a victory over Francis Carmont in his last Octagon appearance. His only defeat in the last three years was a split decision to Tim Boetsch. Always known for his wrestling acumen, Dolloway has shown improved striking in recent fights — including a knockout victory over Cezar “Mutante” Ferreira in last visit to Brazil.

UFC Fight Night 51 is expected to be aired on FOX Sports 1.