Two UFC titles will be up for grabs at UFC 266 on Sept. 25.

Featherweight titleholder Alexander Volkanovski will meet challenger Brian Ortega at the T-Mobile Arena in Las Vegas, and a women's flyweight championship bout between Valentina Shevchenko and Lauren Murphy will serve as the co-main event, UFC president Dana White told ESPN's Brett Okamoto.

The card will also feature Nick Diaz's return to action after a six-year layoff. He'll meet fellow veteran Robbie Lawler in a five-round clash.

The Volkanovski-Ortega matchup is rescheduled from March after the champion needed to withdraw due to COVID-19.

Volkanovski owns a 22-1 record and a 19-fight winning streak that includes two controversial decision victories over former champion Max Holloway.

Ortega is 15-1 with a no-contest. After suffering his first career defeat to Holloway in 2018, he won against Chan Sung Jung in October to vault into the No. 1-contender spot.

Shevchenko is 21-3, and her only two UFC losses have come against two-division champion Amanda Nunes. She hasn't lost since 2017.

Murphy brings a 15-4 record and a five-fight winning streak into the title fight.