Britain's two top heavyweights look set to go toe-to-toe in a bout this autumn and Haye's co-promoter Hearn revealed: 'It's now a case of getting both fighters to cross the line.'
He told the Daily Star: 'It is a fight that will have enormous interest and it could generate one of the biggest pay-per-view figures of all time.
Heavyweight action: David Haye (above) and Tyson
Fury (below) are in negotiations for a fight in August, according to
promoter Eddie Hearn
'We are now at a stage where this is close to happening. It's a brilliant fight between a former world champion and an up-and-coming prospect in Tyson Fury.
'If this fight is going to happen it will be sorted out by the end of this month, that's for sure.'
The potential bout would mark Haye’s return to pay-per-view for the first time since his world heavyweight title loss to Wladimir Klitschko.
The disappointing defeat followed his farcical victory over Audley Harrison and forced Sky to abandon charging fight fans up until Carl Froch’s win over Mikkel Kessler last month.
Getting to know you: Fury poses with Haye's trainer Adam Booth
Enormous interest: Matchroom promoter Eddie
Hearn (centre) believes the fight could be one of the biggest
pay-per-view draws of all time
Fury's uncle and trainer Peter admitted the fight would only not go ahead if there were problems on Haye's side.
He said: 'We want Haye. If the fight does not happen, it won't be down to Tyson.'
Haye has previously claimed he would only return to the ring to face one of the Klitschko brothers.
Early return: Haye previously said he'd only return to the ring to face one of the Klitschko brothers