Tyson Fury will fight Belarus heavyweight Alexander Ustinov in Manchester on Saturday after original opponent Dereck Chisora pulled out with a fractured hand.
Ustinov, who has won 29 of his 30 professional fights, was one of Chisora's sparring partners during preparations for the bout and was the British boxer's opponent when the injury was sustained.
Fury said on Twitter that he "can't wait" for the clash to take place, describing it as a "better fight" than the planned match-up with Chisora.
The 6ft 7in Ustinov, 37, represents a significant challenge for Fury, whose preparations were for a fighter who stands several inches shorter.
Ustinov has beaten Britain's Michael Sprott, David Tua, Monte Barrett and Paolo Vidoz during his pro career, with his sole defeat coming against Kubrat Pulev - Wladimir Klitschko's next opponent in September - in 2012.
"The first thing is I'm happy to still be fighting this Saturday and that the fans will get what they paid for and see a good fight," Fury said.
"We've had a hard training camp and I'm in the shape of my life, expecting to knock out Chisora, but now I'm going to have to take it out on Ustinov and make sure he takes the full force of my anger.
"Strangely, I'm going to break the man who broke Chisora's hand."
Fury has had a difficult 18 months, with the cancellation of two fights with David Haye preceding this latest setback.