Anthony Joshua will fight Tyson Fury on August 14 in either Riyadh or Jeddah in Saudi Arabia, with an official announcement set to be made within a few days.
Talks appeared to have stalled at the start of the week when Fury’s promoter Frank Warren raised concerns over finances, but Hearn insists that they are preparing an official announcement and a series of press conferences.
The Matchroom boss confirmed the deal is made and that only minor details need to be ironed out – and that the rivals will meet twice before the end of the year.
“These are the same people we dealt with before for the Andy Ruiz fight,” Hearn told iFL TV of his dealings with Saudi Arabian officials. “We have to go through the process, which is a long one in terms of paperwork and escrow accounts.
“The financial element of this deal is not a problem at all, but we have to still go through that process, but everything is agreed for the fight.
“We need to start planning for official announcements now and press conferences, which will be a lot of fun and finally be able to give everybody the fight they’ve wanted so badly.
“I’ve been saying all along the fight is happening, and it is happening – finally the other side agree.”
Then undisputed fight is set to feature seven or eight undercard fights with boxers from Matchroom, Queensberry Promotions, Top Rank, and MTK Global.
“Both of these men want to fight, Tyson wanted to fight before the end of July which we’re a few weeks behind and AJ is ready and he wants the fight,” added Hearn.
“The division needs this fight too. The WBO should have ordered Joe Joyce and Oleksandyr Usyk… To be honest with you, because they’ve waited so I long I believe the Joshua-Fury fight will take place before that one.
“If it does, the winner of Fury-Joshua has to fight the winner of Usyk-Joyce, and because we have a second fight planned, that fight will be for the full world title.”
He also confirmed the rematch is planned for December with the UK likely to play host. Joshua and Fury are expected to make in excess of $75million (£53m) from the first fight.