Charles Oliveira is returning to the Octagon…

The 33-year-old Brazilian professional mixed martial artist and Brazilian jiu-jitsu practitioner, a former UFC lightweight champion, will face top contender Beneil Dariush in May.

The UFC hasn’t officially announced the 155-pound bout, but Oliveira referred to it as official on social media, and ESPN sources say Dariush’s side has agreed.

The lightweight fight will take place on May 6 at an event that is expected to be a UFC 288 pay-per-view.

Oliveira (33-9) hasn’t fought since a third-round submission loss to current lightweight champion Islam Makhachev in October. That fight came under unique circumstances in that it was technically for the vacant lightweight title, after Oliveira surrendered the title this past May after missing weight for a defense against Justin Gaethje.

Although the Brazilian wasn’t the official champ when he fought Makhachev, the sport widely viewed him as such until the loss. Prior to the defeat, Oliveira had won 11 in a row.

Dariush (22-4-1) will take an eight-fight win streak into the contest in May. The 33-year-old has a strong case for a title shot now, but he has a history of seeking fights to remain active rather than wait for specific opportunities. Dariush would likely assert himself as the clear No. 1 contender at lightweight with a win. He has never fought Makhachev.

A bantamweight title fight between Aljamain Sterling and Henry Cejudo is slated to headline UFC 288. The UFC has not announced a venue for the date.