Anthony Joshua will fight former UFC star Francis Ngannou in Saudi Arabia, says promoter Eddie Hearn.
Ngannou lost to Tyson Fury on his professional boxing debut in October.
Joshua, 34, was set to face Deontay Wilder after beating Otto Wallin, but the American's loss to Joseph Parker scuppered plans for their big showdown.
Hearn posted "it's a done deal" on X on Friday, and added: "Anthony Joshua v Francis Ngannou collide on a huge night in Riyadh, Saudi Arabia."
A March 9 date has been mentioned, but Hearn said a press conference would be held in London on 15 January with more details about the fight "dropping soon".
Cameroon-born Ngannou, 37, was ranked the number 10 heavyweight by the WBC after he almost stunned WBC heavyweight champion Fury, losing on a controversial split decision in their Saudi Arabia contest.
Saudi organisers had already pencilled in a Joshua-Wilder bout for this year, but the 38-year-old Wilder's defeat by New Zealander Parker on the same card as Briton Joshua's win over Wallin meant a highly-anticipated mega-fight slipped away.
While no contract had been signed, the pair were expected to enter the ring post-fight and announce a deal to fight at some point in early 2024.
Meanwhile, Fury and Oleksandr Usyk will fight to become the first undisputed heavyweight champion since 1999 when they finally clash on 17 February in Saudi Arabia.
Briton Fury, 35, is the WBC champion, with Ukraine's Usyk, 36, holding the WBA, WBO and IBF belts.
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