Anthony Joshua and Tyson Fury have signed a two-fight deal to face each other for the undisputed heavyweight championship, promoter Eddie Hearn has announced.

British rivals Joshua and Fury have been in negotiations for several months to agree showdowns for the four major belts in boxing's glamour division.

Joshua (24-1, 22 KOs) holds the WBA, WBO and IBF belts, having successfully defended his title with a ninth-round stoppage of Kubrat Pulev at Wembley Arena in December.

Fury (30-0-1, 21 KOs) sensationally dethroned Deontay Wilder to claim the WBC crown in February last year but has not boxed since.

A date and venue for the initial encounter are yet to be confirmed, although Hearn – who promotes Joshua under his Matchroom Sport banner – told ESPN on Monday that both parties put pen to paper over the weekend.

"We'd like to get a site deal confirmed in the next month," Hearn said.

"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."

The hurdles to overcome in getting to this point were not inconsiderable, with Fury working under a co-promotional deal with Frank Warren and Bob Arum's Top Rank, both of whom have rival broadcasting agreements to Hearn's contracts with Sky Sports in the UK and DAZN globally.

Fury's most recent bouts have been aired by BT Sport in his homeland and via ESPN in the United States.

The expectation of ongoing coronavirus restrictions makes the prospect of at least the first fight taking place on British soil feel far-fetched, with a return of heavyweight title boxing to the Middle East – where Joshua avenged his only career defeat against Andy Ruiz Jr with a December 2019 points win in Saudi Arabia – appearing most likely.

"I actually feel we've done the hard part," Hearn said. "Speaking for myself, Anthony and his team at 258 management, I know how hard we've worked hard 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. It will be a major, major win for a country that wants to showcase itself."

Some typically idiosyncratic interviews from Fury over recent days, where he stated he had no interest in boxing in the UK again, while claiming to have stopped training in favour of "concentrating on getting me 10 pints of Stella", appeared to cast some doubt upon the Joshua fights getting over the line – especially considering the 32-year-old's previously well-documented struggles with alcohol and depression.

"You never really know with Tyson," Hearn said. "It could be mind games. He could be having a bad day. He could be a little p***** off. Or he could be having a joke.

"One of the fascinations about this fight will be the build-up because they're two totally different characters, two totally different personalities. The mind games will be on another level for this fight. Tyson is very good at that.

"Anthony is excited by that. He's so pumped, so focused, he hasn't stopped training since the Pulev fight. He's like a caged lion. The build-up is going to be epic."

Whenever boxing's matchmakers put together a bout that promises fireworks and destructive drama from the opening bell, pundits and fans alike spit out the same three syllables.

Hagler-Hearns.

Marvin Hagler and Thomas Hearns shared seven minutes and 52 seconds of unfathomable brutality in Las Vegas in April 1985, setting an impossible bar for every all-action fight ever since.

Hagler and Hearns met in their primes as two stars of a golden age in the sport's middle weights. The celebrated "Four Kings" were completed by fellow greats 'Sugar' Ray Leonard and Roberto Duran.

There were nine fights in all between the quartet, spanning 1980 to 1989. Leonard and Duran met three times, with both men going the distance against Hagler. Hearns and Leonard shared 26 rounds over the course of two enthralling bouts separated by almost eight years.

And yet, the comparatively brief period Hearns and Hagler spent in one another's violent orbit stands as the high watermark of the era for many.

After Hagler died aged 66 on Saturday, we look back at three rounds that shook the world.

ROUND ONE

An elongated promotional tour taking in 21 cities whipped up severe animosity between the two fighters, with long-reigning unified middleweight king Hagler brooding over the perceived higher public standing afforded to fellow Americans Leonard and Hearns, along with the latter's withdrawal from their proposed 1982 meeting with a hand injury.

Hearns had showcased terrifying power at welterweight and light-middleweight. He demolished Duran inside two rounds in 1984, at the same Caesars Palace outdoor arena that staged his clash with Hagler.

Therefore, the expectations were of a measured start from the older man, who would draw the sting from a 26-year-old Hearns at a then-unfamiliar weight before taking him into deep waters.

Hagler was not reading from that script.

After eyeballing his foe throughout the introductions, he tore out of his corner at the opening bell and unleashed a wild and winging right hand that Hearns just managed to duck. The tone was set and there would be no let-up.

Hagler's gameplan – insofar as it could be deciphered from underneath the red mist – was to negate Hearns' three-inch reach advantage by attacking the younger man to the body.

Initially, that was a march straight into trouble as Hearns caught him with a left hand coming in and followed up with a right hook to shake Hagler.

The champion held for the briefest of respites before leather began to fly in centre ring – Hagler unleashing his chopping left hook and locating Hearns' chin to force a retreat to the neutral corner.

Hurt, Hearns shot back under heavy fire to escape the peril Hagler had planned on the ropes.

There was a minute gone.

The hunter and hunted patter was established. Hearns clipped Hagler with a left off the back foot to draw him on to a short right. Worryingly for the 'Motor City Cobra', 'Marvellous' was entirely unperturbed.

Hagler's booming straight right was working effectively, but Hearns' blurring fists continued to punctuate a fight in fast forward. A pair of rights found the jaw, still Hagler came. A flashing uppercut, still he came. But there was blood. A lot of it.

"There's blood all over Marvin Hagler's face, I can't tell where it's coming from," yelped commentator Al Bernstein

Seemingly spurred on by the change in circumstances, Hagler forced Hearns into the red corner and got to work, pounding the body. Hearns was sharp in the eye of the storm, soaking up two crunching left hooks and fighting his way out of trouble.

Well, until that unerring Hagler straight right sent him tottering backwards with nine seconds left in the round. By the time the bell sounded, they were trading once more.

Hearns landed 56 of 83 punches in the first round as Hagler connected with 50 of 82. It still beggars belief.

ROUND TWO

"Don't worry about the cut, Marvin," said his cornerman Goody Petronelli, unknowing that there were bigger problems afoot on the other stood.

At some point in the fury of the first three minutes, Hearns had broken his wrecking ball right. This perhaps explained his willingness to begin the second on the jab – that tool of relative conservatism largely lost in the maelstrom of round one.

Hagler met this adjustment with a change of his own. The switch-hitter turned to an orthodox stance for the first time in the fight and landed with a left-right combination.

Regardless, there would be no backwards step from Hagler. Back he went to southpaw, a right jab leaving Hearns disorganised and opening up more opportunities to the body.

A straight right was Hearns' retort along with crisp lefts to head and body, but Hagler shrugged them off and continued to bore forwards with blood all over the place.

His left hook was working like a dream and shuddering rights had Hearns in trouble on the ropes.

When the bell sounded, Hagler's bloody mask and Hearns' exhausted body gave both men the look of beaten fighters.

ROUND THREE

"Just box him, stay away and box him," Emanuel Steward implored Hearns, although the great tactician had reason to sense the bout was slipping away.

Aghast, Steward found one of Hearns' entourage giving him a leg massage before the fight. Combined with the concussive head shots Hagler had landed at will, the result was rubbery limbs that did not convince as the Kronk Gym favourite looked to get on the balls of his feet and skip away at the start of round three.

Hagler's eyes never deviated from a moving target, but his problems were also stacking up.

Referee Richard Steele was increasingly zealous when it came to breaking the fighters up, preventing Hagler from doing the work he wanted to on the inside. After one of the official's interventions, he called the ringside doctor to have a look at the champion's increasingly gruesome cut.

Given Hearns opened the cut with a punch, a TKO defeat was on the cards for Hagler if he was deemed unfit to continue.

But no referee or no doctor was stopping this fight. Hagler decided it was time to take care of adjudication himself.

He had started to measure Hearns' increasingly predictable retreats, and a right to the side of the head saw his opponent stagger sidewards across the right, almost turning his back. Hagler knew the time was now.

A follow-up right to the temple robbed Hearns of any remaining equilibrium and another to the jaw saw him sag back before collapsing downwards, the breeze of Hagler's superfluous follow-up shots doing nothing to rouse him.

Flat on his back, Hearns tried valiantly to beat Steele's count, but a valedictory triumph belonged to Hagler after a cacophony of violent mayhem and savagery that remains celebrated to this day.