The Tyson Fury-Anthony Joshua card just got a lot more dangerous.

Former heavyweight champion Deontay Wilder will face unbeaten cruiserweight champion Jai Opetaia in the co-main event on Dec. 11 at Principality Stadium in Cardiff, Wales. The matchup was announced Wednesday. The whole card will stream live worldwide on Netflix.

"The co-main event is officially set," Dana White said on social media. "These two guys have a combined 67 knockouts. You do not want to miss this fight."

Opetaia takes the big gamble

Opetaia is 31-0 and widely seen as the best cruiserweight in the world. The Australian southpaw won the IBF title in 2022 and has not lost since. He also boxed at the 2012 London Olympics when he was just 16.

This will be his heavyweight debut. His opponent is one of the hardest punchers the sport has ever seen.

White called it "a very dangerous fight for him considering where he sits in his division right now."

Wilder's second wind

Wilder, 41, is 45-4-1 with 43 knockouts. The Tuscaloosa, Alabama, native held the WBC heavyweight title from 2015 to 2020 and made 10 successful defenses before losing it to Fury.

Many thought he was finished after back-to-back losses to Joseph Parker and Zhilei Zhang. He has since won twice, most recently beating Derek Chisora by split decision in April.

Opetaia is 10 years younger.

Main event

Fury and Joshua finally meet after years of talks about a fight between the two British former champions.

The undercard takes place Friday night in Cardiff. The main event ring walks are expected around 2 a.m. local time to line up with prime time for American viewers.