Anthony Joshua has signed his contract to fight Oleksandr Usyk in Saudi Arabia in August with a formal announcement set for next week.
Usyk, 35, beat Joshua on points last year to win the WBA (Super), WBO and IBF title but the rematch has suffered months of delays.
But Joshua’s promoter Eddie Hearn has confirmed paperwork is now “done”.
“This fight is on and you will get an official announcement early next week,” Hearn told 5 Live.
The delays had been in part caused by Usyk’s return to Ukraine after the invasion of the country by Russia, however broadcast deals have also been a factor with a suggestion Joshua could move from Sky Sports to DAZN.
A date of 23 July was pencilled in for the rematch but Usyk’s promoter Oleksandr Krasyuk said they have been told to prepare for 20 August.
“[AJ] understands that in a fight of this magnitude, things do take time. It’s taken time but we’re in a great place. He’s been training throughout, so has Oleksandr Usyk,” Hearn said of the delay.
“AJ is more confident than I’ve ever seen him going into a fight. We believe he’s going to win the fight.”
Meanwhile, Tyson Fury’s promoter Frank Warren has denied the heavyweight is in talks to face the winner of Joshua v Usyk.
Fury, 33, suggested he would retire after his win against Dillian Whyte in April, but is yet to be stripped of his WBC title.