Chael Sonnen-Wanderlei Silva official for May 31 card in Sao Paulo, Brazil

NATAL, Brazil – The UFC’s return to Brazil in May now is official, and the promotion will return to Sao Paulo with Chael Sonnen and Wanderlei Silva in the main event.

The light heavyweight bout in February had been moved from UFC 173 in Las Vegas to a May 31 card in Brazil. But in recent weeks, both the location of that card, and the definitive nature of its proposed main event, had been unconfirmed.

On Sunday in Brazil, though, UFC executive Grace Tourinho confirmed to MMAjunkie that Sao Paulo will play host, and that the ink apparently is dry enough on the bout agreement between Sonnen (28-14-1 MMA, 7-6 UFC) and Silva (35-12-1 MMA, 5-7 UFC) to make things official. Tourinho revealed the news at the post-event news conference for UFC Fight Night 38, which took place at Ginasio Nelio Dias in Natal, Rio Grande do Norte, Brazil.

The card, likely to be part of the UFC “Fight Night” series, will take place at Ibirapuera Gymnasium in Sao Paulo, which also played host to UFC on FX 7 in January 2013, an event headlined by Brazilian favorite Vitor Belfort, who knocked out Michael Bisping in the main event.

Sonnen and Silva are serving as coaches on “The Ultimate Fighter: Brazil 3,” which currently is streaming on UFC Fight Pass after filming wrapped earlier this year.

Sonnen, a former middleweight title challenger, is coming off a TKO loss to Rashad Evans in a 205-pound bout at UFC 167 in November. That dropped him back into the loss column after a “Submission of the Night” win over Mauricio “Shogun” Rua in August, a win that snapped a two-fight skid of title losses to then-middleweight champ Anderson Silva and light-heavyweight titleholder Jon Jones.

Wanderlei Silva has not fought in nearly a year. This past March, the vet stopped Brian Stann with a second-round “Knockout of the Night” in Japan, where he made his name fighting for PRIDE. “The Axe Murderer” will be chasing his first winning streak since 2005-2006.

For more on “UFC Fight Night: Sonnen vs. Silva,” stay tuned to the UFC Rumors section of the site.