Briton Anthony Joshua will face Joseph Parker in a heavyweight unification world championship in Cardiff on March 31.
Joshua, 28, has the IBF and AMB belts, while the New Zealander Parker is the WBO champion.
The stadium of the Principality of Cardiff, where Joshua successfully defended his titles against Carlos Takam in October, will host the fight.
Joshua promoter Eddie Hearn tweeted to confirm the fight, saying: "That's it!"
He added: "It is the first time in history that two reigning heavyweight champions have fought in Britain."
Parker & # 39; s representative David Higgins arrived in the United Kingdom last week to finalize a deal. The talks had previously stalled on how the purse would be split, but a compromise was reached last month that will see Parker, 25, win 30-35%.
Parker is unbeaten in his 24 professional fights, with 18 of those victories by knockout.
Joshua became IBF heavyweight champion at defeating Charles Martin at the O2 Arena in London in April 2016.
The following April, he added the WBA belt for beating Wladimir Klitschko against 90,000 fans at Wembley Stadium.
Whoever wins in March will surely face undefeated American Deontay Wilder, who has the fourth belt in the heavyweight division. No boxer has had all four heavyweight belts simultaneously.
Parker's camp has been pushing for the fight since Joshua defeated Takam last year.
They organized a press conference in November clips of Joshua being shot down in his amateur days and offered £ 20,000 to anyone with images of his shooting down.