Tyson Fury will face Anthony Joshua in an all-British heavyweight showdown in Cardiff on December 11.
The long-awaited clash had initially been linked with venues in New York and London before promoters settled on the Principality Stadium in the Welsh capital.
After months of negotiations that threatened to scupper the fight as Fury called for a rematch with Oleksandr Usyk, Saudi Arabian boxing powerbroker Turki Alalshikh announced the venue and date for the bout on Thursday.
"For 15 years no one has been able to make this fight," he wrote on social media.
"Back in April, I said that any announcement would come from me. I can now confirm that Fury Vs Joshua will be coming to the UK, as I promised British boxing fans. The time for talking is over..."
Choosing the 80,000-capacity stadium in Cardiff, which has hosted the Champions League and FA Cup finals, as well as Wales national team matches in football and rugby, allows both fighters to finally start their preparations for the eagerly-anticipated clash.
The fight, one of the biggest in British boxing history, will be broadcast on streaming service Netflix.
Fury, 38, defeated 46-year-old Mariusz Wach in Thailand in his most recent bout in July.
Joshua, 36, survived a pair of first-round knockdowns to beat the unheralded Kristian Prenga in his last fight two months ago.
The former two-time world champions had already signed contracts for the bout earlier this year, but the date and venue had yet to be confirmed.
Wembley in London and New York's Madison Square Garden had been the leading contenders to stage the fight before the Cardiff decision.
"Forever indebted to the UK public for their support of Anthony Joshua. We couldn't have got this over the line without you," his promoter Eddie Hearn said.
More than a decade in the making, the bout between the former two-time world champions is the culmination of numerous false starts and spats before Thursday's confirmation.
The fight could reportedly take place in the early hours UK time in a bid to satisfy television audiences in the United States.
"I am inspiring a generation," Joshua posted on Instagram after the fight was announced.
Fury has won 36 of his 39 fights and held the WBC, WBO and IBF heavyweight belts during his colourful career.
The self-styled 'Gypsy King' was twice beaten by Usyk in world title bouts in 2024.
Joshua has 30 wins from 34 fights, holding the WBO and IBF titles at various stages before a pair of losses to Usyk in 2021 and 2022.
Fury and Joshua will start the pre-match hype in a press conference on September 30 in London.
"Two of the best heavyweights of this generation, finally in the ring together," Alalshikh said.
"This will be one of the biggest fights in boxing history, I am very happy to make this fight happen for the fans."