Tyson Fury and Oleksandr Usyk have “signed” contracts to meet in an undisputed heavyweight title fight. Fury said in a post on Instagram that he will fight Usyk for all four belts in Saudi Arabia, in what would be the first undisputed heavyweight title bout in a generation. Fury did not disclose any further details about the fight but his promoter Frank Warren confirmed the deal had been done. “Delighted to finally get this fight signed,” Warren said. “This is the biggest fight that could possibly be made in our sport. “The heavyweights always spark the imagination of the fans, and I have no doubt this will be the biggest boxing event of the century.” The date of the contest, which will take place in Riyadh, has not been announced, however. Fury and Usyk had previously been in talks over a heavyweight showdown but discussions collapsed ahead of a proposed April bout at Wembley Stadium. Ukrainian Usyk, 36 , is unbeaten in 21 fights, having last knocked out Daniel Dubois last month in Poland. Fury has not been in action since knocking out Dereck Chisora last December, and the WBC champion, 35, is also unbeaten in 34 fights - with 33 wins and a draw. “You can’t run rabbit run anymore Usyk, you’re getting it,” Fury wrote on Instagram. Fury is set to face former UFC world heavyweight champion Francis Ngannou in a crossover fight on October 28, but his WBC belt will not be on the line. Britain’s Lennox Lewis was heavyweight boxing's last undisputed champion in 1999. Read More Ngannou reveals how Jones mega-fight can happen after Fury boxing match Tyson Fury ‘tried to pay’ to halt filming of Netflix reality show KP’s World Cup preview and Tyson Fury’s new arrival – Monday’s sporting social Joe Joyce on knockouts, oil painting, and teaching 60-year-olds to swim How Canelo, boxing’s final throwback, can further cement his sporting legacy Who is fighting on the Canelo vs Charlo undercard?