And in a much-anticipated feature bout, Nick Diaz will return to the Octagon for the first time in over six years to take on Robbie Lawler. The two met way back in 2004, with Diaz scoring a second-round knockout.
Volkanovski (22-1) has won 19 fights in a row, the longest active unbeaten streak among fighters currently on the UFC roster. He is No. 6 in the ESPN men's featherweight rankings.
Ortega (15-1) will be making his second title challenge. He lost to then-champ Max Holloway in 2018.
The main card will be on pay-per-view, which can be purchased here.
The five-fight PPV card will begin at 10 p.m. ET, and the action will start at 6 p.m. ET with early prelims on ESPN2 and ESPN+. Prelims will start at 8 p.m. ET, also on ESPN and ESPN+.
How to watch the fights
Watch the PPV and all other fights on ESPN+. Get ESPN+ here.
Don't have ESPN? Get instant access.
Purchased the fight on your phone and want to stream on your TV? Find out how here.
There's also FightCenter, which offers live updates for every UFC card.
Saturday's fight card
ESPN+ PPV, 10 p.m. ET
Men's featherweight title fight: Alexander Volkanovski (c) vs. Brian Ortega
Women's flyweight title fight: Valentina Shevchenko (c) vs. Lauren Murphy
Middleweight: Nick Diaz vs. Robbie Lawler
Heavyweight: Curtis Blaydes vs. Jairzinho Rozenstruik
Women's flyweight: Jessica Andrade vs. Cynthia Calvillo
ESPN/ESPN+, 8 p.m. ET
Men's bantamweight: Marlon Moraes vs. Merab Dvalishvili
Lightweight: Dan Hooker vs. Nasrat Haqparast
Heavyweight: Shamil Abdurakhimov vs. Chris Daukaus
Women's flyweight: Roxanne Modafferi vs. Taila Santos
ESPN+, 6 p.m. ET
Lightweight: Uros Medic vs. Jalin Turner
Middleweight: Cody Brundage vs. Nick Maximov
Welterweight: Matthew Semelsberger vs. Martin Sano
Men's featherweight: Jonathan Pearce vs. Omar Morales