Anthony Joshua and Tyson Fury stand a chance to earn about £70 million each if they stage their heavyweight unification bout next year.
The two British boxers are in possession of all the belts in their category and they have reached an agreement to face-off in a two-legged encounter in 2021.
Reports claim that the winner of the first leg would win double of his take-home when they clash in the final round of the meeting according to the deal they agreed in principle.
Both fighters have been throwing banter at each other since February after Fury handed Deontay Wilder his first defeat, and was crowned the new WBC champion.
However, the Gypsy King will have to repeat his dominance over the Bronze Bomber, while Joshua battle Kubrat Pulev before this historic encounter can take place.
The Mirror reports that both boxers will earn about £60m and £70m each once they put pen to paper on an agreement, while the winner earns 60 percent of the purse in a rematch.
Looking like a similar deal signed between Fury and Wilder before their rematch.
Fury was said to have earned around £40m from his victory in February.
However, Saudi Arabia's involvement in his fight with Joshua could further improve the amount both are expected to win.
Reports claim the Middle Eastern state is leading the list of hosts for the undisputed fight having successfully staged Joshua's rematch with Andy Ruiz Jr last December.
While Las Vegas and London's Wembley Stadium are also considered for the epic fight between the Britons, but the latter is more likely to host any second installment.
Fury's handler Frank Warren said: "At this point, we can confirm no contracts have been signed between any of the concerned parties, nor have any specifics been agreed regarding venues, dates and numerous other key terms.
"Both sides do accept that any prospective fight will demand a 50/50 split and both sides accept there will be a rematch.
"Obviously, we are keen to make the fight that British fans demand and will continue negotiations in order to deliver Tyson his shot at becoming the undisputed heavyweight champion of the world.
"Things are going in the right direction and we couldn't be happier that a potential mega-fight is in reach."