Promoter Eddie Hearn says rival world heavyweight champions Anthony Joshua and Tyson Fury "have agreed to the basics" of a deal to fight two times in 2021.
There is no signed contract yet, with the first fight likely to happen in the summer of 2021. Venues and dates have yet to be agreed to, and both English boxers have defenses of their titles to get through for the two fights to happen.
"We have agreed to the basics of the deal, a two-fight deal," Hearn, who promotes Joshua, told ESPN. "The hardest part is to agree to the financial element of the deal. We have agreed with Tyson Fury and the team, and we can now move forward with finalizing the smaller parts of the deal. The good news for fight fans is that we have agreed to do the two fights and we can now go and dot the I's and cross the T's.
"They also have fights in between to make and get through, and that's another issue."
Fury, the reigning WBC and lineal heavyweight champion, defeated Deontay Wilder in February. Wilder exercised his contractual right to an immediate third fight, which was planned for July until the coronavirus pandemic caused postponements and cancellations across the boxing world. That fight seems likely to happen late this year, according to Top Rank's Bob Arum.
Joshua, the WBO, WBA and IBF heavyweight champion, defeated Andy Ruiz to regain his three belts after a shocking loss in June 2019. Joshua had his mandatory bout with Kubrat Pulev, scheduled for June 20, postponed because of the pandemic.
Fury is due to face another Briton, Dillian Whyte, in a mandatory defense early in 2021.
"Who knows what's going to happen with Deontay Wilder, but we [Matchroom Sport] want Dillian Whyte to fight for the world title, and he is supposed to fight Tyson Fury, the WBC champion, by February 2021," Hearn said. "There are obstacles to overcome, but the good news is that we are moving forward."
If Joshua and Fury retain their titles, it would set the stage for a unified heavyweight champion for the first time in over 20 years.
ESPN previously reported that talks between the two sides were underway, with a potential location being Saudi Arabia or elsewhere on the Arabian Peninsula.
"Certainly, they're going to [be] making a big play [for the Middle East]," Hearn said. "But they're two British guys, so in a dream scenario -- especially for British fight fans -- that fight would take place in Britain. But obviously there's going to be significant offers, and there already has been to stage this fight, the biggest fight in boxing, one of the biggest fights of all time, and it's for the undisputed heavyweight championship.
"So we'll be looking at different options, speaking to the Fury team and making sure fighters are in agreement where the fight should take place."
Fury tweeted about the agreement to face Joshua, saying in a video: "The biggest fight in British boxing history has just been agreed. ... Two-fight deal, Tyson Fury vs. Anthony Joshua next year. One problem: I've just got to smash Deontay Wilder's face right in in the next fight, and then we go into the Joshua fight next year."
Hearn said Fury-Joshua for all four world heavyweight titles would be the biggest fight in British boxing history and set pay-per-view records in the United Kingdom.
"It's probably the biggest fight of all time for British sport," Hearn told ESPN. "There has been nothing to compare it to, and there never will be again."
Frank Warren, who co-promotes Fury along Arum, told ESPN that a 50-50 split has been agreed to, but he downplayed the significance of Hearn's comments and insisted no contract had been signed.
"It was always going to be a 50-50 deal and a rematch. Other than that, nothing has been agreed, no contract," Warren told ESPN. "It's looking like Wilder [as Fury's next fight] toward the end of the year, unless something comes up.
"I hope the Joshua fight happens, and I would like it this year if we can. These guys [Fury, Joshua] could get between $60 [million] to $70 million each from one fight against each other, double that if there's a rematch, in one year."
As for the progress of Fury-Wilder III, Arum said: "It's set, but we're looking for the site. Will we be able to do it for the spectators, even partially, in the United States? If not, can we do it with spectators in Macao or Australia? That's what we're exploring now."
Information from ESPN's Nick Parkinson and Steve Kim was used in this report.