Anthony Joshua will defend his WBA, IBF and WBO heavyweight world titles against mandatory challenger Oleksandr Usyk on September 25 at Tottenham Hotspur Stadium in London.
The unified champion was hoping to fight for the final belt in an undisputed clash with Tyson Fury this summer, but plans collapsed last month.
As a result, the WBO ordered AJ to defend against his overdue mandatory Usyk.
The parties agreed terms and this bout has now been made official.
Usyk previously won all of the belts at cruiserweight as undisputed champion.
Since moving up to heavyweight, he became automatic mandatory and has recorded wins over Chazz Witherspoon and Derek Chisora to prepare him for a title shot.
“The date is set and we are fully locked in,” said Joshua.
“September 25, Tottenham Hotspur Stadium, I put it all on the line again and it’s time to defend my crown.
“We are two Olympic Gold medallists who have fought our way to the top and never avoided challenges.
“The stadium is exceptional, the atmosphere will be electric, I’m honoured to be the first person to fight in such an awe inspiring venue.
“The stage is set and I am ready to handle business.”
Usyk simply said: “The path will be mastered by the walking one.”