Tyson Fury says a two-fight deal with Anthony Joshua is in place, with the two heavyweight champions set to meet in 2021.
Joshua regained the IBF, WBA and WBO titles from Andy Ruiz Jr in December 2019, while Fury defeated Deontay Wilder in February to gain the WBC strap.
Fury posted on Instagram to say an agreement had been reached, though he must first win a trilogy fight against Wilder.
"I'm just after getting off the phone with [broker] Daniel Kinahan. He's just informed me that the biggest fight in British boxing history has just been agreed," said Fury. "Big shout out Dan, he got this done, literally over the line, a two-fight deal, Tyson Fury versus 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.
"So there we are, the Gypsy King versus AJ is on for next year but there's a hurdle in the road called the Bronze Bomber, AKA the Knockout King, and I will get right onto him and knock him spark out and then get onto the next fight."
Prior to Fury's comments, Joshua's promoter Eddie Hearn said the two fighters had agreed on the financial aspects of the deal.
"We're making great progress," Hearn told Sky Sports. "There is still a lot to overcome. We are looking at venues and dates.
"We have the Dillian Whyte mandatory which is due before this fight. It's fair to say [Joshua and Fury] are in agreement regarding the financial terms of the fight.
"We've been talking to [Fury's management team] MTK, giving them the assurances from Joshua's side that all the details on the structure of the deal is approved from our side. And it is from Fury's side, as well.
"We're in a good place. It's fair to say that, in principle, both guys have agreed to that fight. Two fights.
"[There's] a lot to overcome in the meantime. We're moving in the right direction. I'm confident that both guys have giving their blessing for the fight to go ahead.
"The most difficult part of any deal is the financial element. I believe we're in a great place where both guys have agreed to what that should be.
"We have not signed contracts because there are still things to be worked out.
"We're pushing towards a place where they can be drafted, for 2021. Both guys are in agreement. The structure of the deal has been put forward and agreed to by both parties."
Joshua is due to fight Kubrat Pulev in October or November but is currently injured, having sustained a knee problem while training.
He was pictured on crutches while attending a Black Lives Matter protest in Watford last week, with his left knee in a brace.