Tyson Fury will take on Oleksandr Usyk in a historic undisputed heavyweight showdown in Saudi Arabia, promoters announced on Friday.
The date of the contest, which will take place in Riyadh, has not yet been announced, though reports suggest December 23 is the target date.
Ukraine's Usyk holds the WBA, WBO and IBF heavyweight belts, while Britain's Fury is the reigning WBC heavyweight champion.
The winner of the bout will become the first undisputed heavyweight champion of the four-belt era.
"This is the biggest fight that could possibly be made in our sport," said Fury's promoter Frank Warren.
"The heavyweights always spark the imagination of the fans, and I have no doubt this will be the biggest boxing event of the century."
Lennox Lewis is the last recognised undisputed champion in the division 23 years ago.
Neither fighter has been beaten in their professional careers.
Fury has won 33 fights with one draw since turning professional in 2008.
Usyk has won all 21 of his bouts, but defended his titles against Britain's Daniel Dubois in controversial fashion in August.
Dubois claimed he had been "cheated" out of victory after referee Luis Pabon ruled he had struck Usyk with a low blow in the fifth round, which led to a lengthy delay.
"I can't believe that it's happening but it is," said Usyk's promoter Alexander Krassyuk.
"Difficult to express my admiration for being part of the biggest heavyweight fight of the century. Respect to Tyson for his courage."
Fury, 35, is due to fight former UFC world heavyweight champion Francis Ngannou on October 28 in Riyadh, when his WBC title will not be on the line.
"I do what I say. I say what I do. Undisputed. This is the Gypsy King era," Fury posted on Instagram. "You can't rabbit run anymore Usyk."
- Saudi stage controversial -
A proposed unification fight at Wembley in April fell through and the decision to stage the contest in Saudi Arabia is likely to attack criticism given concerns over the country's human rights record.
The Gulf state has hosted a number of high-profile bouts in recent years, including Usyk's win against Anthony Joshua in Jeddah last year.
Saudi Arabia has lavished hundreds of millions of dollars on sporting events as part of a strategy critics describe as "sportswashing."
The conservative monarchy executed 81 people in a single day last year, outlaws homosexuality and triggered international condemnation when journalist Jamal Khashoggi was murdered in the Saudi consulate in Istanbul in 2018.
Fury won his first world title after dethroning Wladimir Klitschko in 2015, before taking a hiatus from the sport during which he suffered from mental health problems.
He returned more than two-and-a-half years later and beat Deontay Wilder in 2020 to become WBC champion after their first bout was controversially declared a draw.
Fury won a third fight with hard-hitting Wilder and has since defended his belt against Britons Dillian Whyte and Derek Chisora.
Usyk shot to fame by winning heavyweight gold at the 2012 Olympics.
He went onto become undisputed world champion at cruiserweight before switching to the heavyweight division in 2019.
Usyk shocked Joshua at the Tottenham Hotspur Stadium to claim his heavyweight belts in 2021 and defeated the Britain again in a rematch before getting the better of Dubois.
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