Anthony Joshua will face Oleksandr Usyk on 25 September, Eddie Hearn has confirmed.
Joshua, the WBA, WBO and IBF heavyweight title holder, was due to have an all-British heavyweight showdown with Tyson Fury this summer but a legal ruling in the United States wrecked a proposed fight in Saudi Arabia on 14 August.
An arbitration hearing upheld a claim from fellow heavyweight Deontay Wilder that he was contractually owed a third fight with WBC champion Fury, with Joshua then labelling his countryman a "fraud" on Twitter.
It means Joshua will now face Usyk in September, while Fury will take on Wilder to complete a trilogy of fights between the two on 24 July. Victory for both Britons would fuel more talk of a potential undisputed bout.
"Joshua v Usyk announcement, don't want to say two weeks as you guys are bored of me saying that," Hearn said on Instagram live.
"September 25 is the date."
With the prospect of an all-British heavyweight contest over for now, Joshua has turned his focus to an expected meeting with Ukrainian boxer Usyk.
The Tottenham Hotspur Stadium is likely to host the bout.