Khan and Brook to fight in February
Amir Khan will face fellow former world champion Kell Brook at the AO Arena in Manchester on 19 February.
Brook, 35, has not fought since being stopped in the fourth round by American Terence Crawford in November 2020, while Khan won a points decision over Australia's Billy Dib in January.
The fight will be on pay-per-view in the UK under the Boxxer promotion.
At a media conference in London to announce the fight, Khan and Brook engaged in a head-to-head and within seconds had to be separated by security.
"Amir Khan will hit the deck for the final time," Brook later said, adding that his rival had never shown him the respect he deserved and accused him of running away from taking the fight.
"I'm coming levels down taking this fight," Khan said. "I've fought the best in the world and conquered America".
Khan boasts a professional record of 34 wins with five defeats, having shot to stardom after winning silver at the 2004 Olympic Games.
The 34-year-old Bolton fighter won his first world title in his 22nd fight when he defeated Andriy Kotelnik for the WBA light-welterweight belt in 2009, and has also held the IBF title in 2011.
Sheffield's Brook has won 29 bouts with three defeats and was IBF welterweight champion between August 2014 and May 2017.
The fight has been a long time coming, with a rivalry which dates back more than a decade.
In 2010, when Khan held the WBA super-lightweight title, Brook called out the champion. Two years later, in October 2012, the fighters sat side-by-side on Sky Sports boxing show Ringside, with both men relaying their own versions of sparring stories on how they "schooled" the other.
At Monday's fight announcement, Khan once again spoke of how he supposedly "schooled Brook with one hand" which led to his inclusion in the Team GB Olympics squad.
The fight did not materialise as Khan relocated to the United States. Despite back-to-back losses against Lamont Peterson via a controversial split decision and a knockout defeat by Danny Garcia, he was still a big draw in the US and recorded impressive wins against Luis Collazo and Devon Alexander.
Meanwhile, Brook focused on his own charge towards a world title and enjoyed arguably his greatest night in the sport in 2014 when he defeated American Shawn Porter on points in California to become IBF welterweight champion.
After Brook defended that title with a fourth-round victory over Jo Jo Dan the following year, he once again called out Khan.
But Khan said "Brook has to wait" and instead tried to pursue fights with pound-for-pound stars Floyd Mayweather and Manny Pacquiao, bouts he felt would have a greater global appeal.
In May 2016, Khan moved up weight divisions and was sensationally knocked out by Mexican Saul 'Canelo' Alvarez.
In September 2016, Brook suffered a broken right eye socket in a middleweight defeat by Gennadiy Golovkin, then eight months later he broke his left eye socket - and lost his IBF welterweight title - when he was stopped by Errol Spence Jr.
Two years later, Brook said Amir Khan has "let the public down" and blamed him for a fight between the two not taking place.
Both boxers tasted defeat again when they came up short against Crawford, Khan being pulled out by his corner in the sixth round after alleging he was hit by a low blow in their 2019 bout.
Khan and Brook have both fought just four times in the past three and a half years. By the time they meet in Manchester, they will have been out of the ring for more than a year.
With losses on their records, inactivity and both arguably past their prime, it seemed a clash between Khan and Brook would pass us by.
'Past their prime but deserving of a pay day'
While some fans may feel it is a case of 'better late than never', Khan v Book is not the fight it once could have been. At one point, this was the biggest all-British clash in boxing and could have sold out any stadium in the country.
Although they may be far from being in their prime, there is genuine animosity between two fighters who have traded words for several years. Boxing has treated us to a plethora of 'grudges' between rivals in the past, and there are not many bigger than this.
The fun build-up has already started. At the fight announcement, Brook accused Khan of ducking him and focusing on fame and celebrity status, while Khan was still dismissing Brook as being beneath him. We even had both their dads at the top table.
There are suggestions from some in boxing - including Matchroom Boxing promoter Eddie Hearn - that both fighters are searching for one last pay day. Khan and Brook have treated us to some magnificent nights in the sport; from Khan 'cracking America' and a willingness to always take on the best to Brook entertaining us with some sublime performances, none better than his win against Porter.
For all they have achieved in the sport, and the way in which they have represented British boxing on the world scene, perhaps they are deserving of that pay day.