Usyk, who had held the WBA, WBC and IBF belts, has been the world undisputed cruiserweight and heavyweight champion.
Athletes from both countries will compete without national flags, anthems, logos or uniforms in World Boxing events.
Promoter Eddie Hearn confirmed that Joshua and Fury have inked a deal for a heavyweight boxing showdown later this year.
Tyson Fury beats Arslanbek Makhmudov in a unanimous points decision as he makes his heavyweight comeback.
Tyson Fury returns lighter than his last fight but still weighs in three pounds heavier than Arslanbek Makhmudov.
While eyeing a fight with Anthony Joshua, Fury first faces a Russian-born heavyweight who wrestled a bear for fun.
Tyson Fury comes out of retirement to fight devastating puncher Arslanbek Makhmudov at the Tottenham Hotspur Stadium.
Fury, who returns to the ring against Makhmudov on Saturday, says he wants to face his compatriot Joshua next.
Lin Yu-ting wins a medal in her first competitive fight since a gender eligibility row overshadowed her Olympic win.
Former WBC champion comes out on top in the closely contested fight against his British opponent in London.
