The two heavyweight world champions agreed on terms in principle last year but have now put pen to paper after contracts were finalised.

The first fight is expected to take place in June or July with Saudi Arabia in pole position to play host with both fighters set to earn £100 million. And the winner will be crowned the first undisputed heavyweight world champion since Lennox Lewis in 1999 after the WBO agreed to waive Joshua’s mandatory responsibilities.

Negotiations will now continue over when and where the fight would take place with as many as eight countries throwing their hat into the ring.

Promoter Eddie Hearn said: “We’d like to get a site deal confirmed in the next month.

“The hard part is always getting everybody to put pen to paper but this was a major effort from all parties to get this over the line. You had rival promoters, rival networks, and rival fighters.

“I actually feel we’ve done the hard part. Speaking for myself, Anthony and his team at 258 management, I know how hard we’ve worked these last couple of months and I just feel that this fight is so big it’s not a difficult sell.

“We’ve already had approaches from eight or nine sites. The offers have come from multiple countries in the Middle East, from Asia, Eastern Europe, and America.

“This is the biggest fight in boxing and one of the biggest sporting events in the world,” Hearn said. “It will be a major, major win for a country that wants to showcase itself.”

Having agreed a 50/50 purse split last summer, the biggest remaining hurdle was Joshua’s clash with Kubrat Pulev but the Brit stopped his mandatory challenger in the ninth round last December.

The Olympic champion then risked being stripped of one of his three titles if he did not fight Oleksandr Usyk before taking on Fury – but the WBO has relented and Usyk will instead face Joe Joyce for the interim belt.

The winner will then likely be upgraded to full champion status with the victor of Joshua vs Fury expected to relinquish the belt in order to stage a rematch later this year.

Joshua and Fury have been on a collision course since the latter stopped Deontay Wilder in their rematch last February.

But an all-British clash was initially dependent on Fury beating Wilder again in their trilogy fight – and Joshua seeing off the challenge of Pulev.

The coronavirus crisis then played havoc with the boxing schedule and both fights were pushed back to December.

But when Fury was asked to postpone his title defence until the new year, he refused and walked away from his rivalry with Wilder.

That left him free to face Joshua who dropped Pulev three times en-route to victory.

The champion was reluctant to call out Fury in his post-fight interview but negotiations quickly resumed and a deal was eventually struck.