American Deontay Wilder will fight Australia's Jai Opetaia on the undercard of Tyson Fury v Anthony Joshua in December.

The bout will serve as the co-main event for the long-awaited all-British heavyweight fight, with the WBA 'super' heavyweight title on the line at Cardiff's Principality Stadium.

Unbeaten WBA 'regular' cruiserweight champion Opetaia, 31, will step up to heavyweight for the first time to fight Wilder, a former world champion with 43 knockouts.

Wilder (45-4-1, 43 KOs) will hope to re-establish himself among the heavyweight elite, while Opetaia (31-0, 24 KOs) could be eyeing a fresh challenge, after years of dominance at cruiserweight.

Wilder, 41, held the WBC heavyweight title from 2015 to 2020 and is regarded as one of the most feared punchers of his generation.

The American also enjoyed an epic trilogy with Fury, but came out on the losing side with a draw and two defeats.

Wilder had also been close to facing Joshua but a knockout loss against China's Zhilei Zhang in June 2024 derailed the potential bout.

Tickets for the main event sold out in under an hour, despite the ringwalks being expected to start around 01:00 GMT on Saturday, 12 December, following a short live music performance, and the stadium will remain open until 03:30.

The remaining bouts on the undercard are still to be announced, with Wales' former IBF super-featherweight champion Joe Cordina thought to be in negotiations to fight Manny Pacquiao.