Anthony Joshua will defend his WBA, WBO and IBF heavyweight titles against Alexander Povetkin at Wembley on September 22, his promoter Eddie Hearn has announced.
Russia's Povetkin is the mandatory challenger to his WBA title, and by fighting him Joshua should secure greater freedom in selecting his next opponent.
The 28-year-old Briton had been in training while negotiations with WBC champion Deontay Wilder stalled, but could yet fight the American in April 2019.
Joshua was last in action in March when he defeated New Zealander Joseph Parker in Cardiff to add the WBO title to his WBA and IBF heavyweight crowns, while also extending his perfect record to 21 successive wins.
"I can't wait to get back in the ring, the end of March feels a long time ago now," said Joshua.
"Povetkin is a serious challenge that I will prepare meticulously for. He has serious pedigree and only a fool would underestimate what he brings to the table.
"Training hasn't stopped for me, but the next 10 weeks ahead will be intense both mentally and physically. I will push myself to breaking point to make sure I am in peak condition for another huge night for British boxing at Wembley Stadium on September 22nd."
The 38-year-old Povetkin, who stopped David Price on the undercard of Joshua's victory over Parker, said: "The battle for the world title has always been my goal.
"I fought for the moment to face the strongest in the world and on September 22nd get my opportunity."