JACKSONVILLE, Fla. — Alexander Volkanovski‘s latest featherweight title defense is official.

Volkanovski and Chan Sung Jung, better known as “The Korean Zombie,” both weighed in Friday at 144.5 pounds. Volkanovski will defend his UFC featherweight belt against Jung in the main event of UFC 273 on Saturday at VyStar Veterans Memorial Arena.

ESPN has Volkanovski ranked No. 4 in the world pound-for-pound. At featherweight, Volkanovski is ranked No. 1 and Jung is No. 9.

Volkanovski (23-1) has won 20 fights in a row, including his first 10 in the UFC. The Australia native is coming off a unanimous decision win over Brian Ortega at UFC 266 last September. Volkanovski, 33, has two successful title defenses after beating Max Holloway to win the belt at UFC 245 in December 2019.

Jung (17-6) is coming off a unanimous decision win over Dan Ige last June. The Korea native has won three of his past four fights. Jung, 35, challenged for the featherweight title in 2013 against Jose Aldo, the longest period of time between title fights in UFC history.

In the co-main event, champion Aljamain Sterling and interim champ Petr Yan will unify the UFC bantamweight title. Sterling weighed in at 134.5 pounds and Yan hit the mark at 134.

Sterling (20-3) won the UFC bantamweight title via disqualification when Yan landed an illegal knee on him at UFC 259 in March 2021. The 32-year-old New York native has won six straight.

Yan (16-2) is ESPN’s No. 6-ranked pound-for-pound fighter. The 29-year-old Russian has won 11 of his past 12 fights, the lone loss to Sterling. Yan won the interim title by beating Cory Sandhagen via unanimous decision at UFC 267 last October.

Another highly anticipated matchup at UFC 273 pits former title challenger Gilbert Burns against Khamzat Chimaev, one of the best prospects in UFC history. Both men weighed in at 170 pounds on the dot.