Hamburg - Wladimir Klitschko will defend his IBF and WBO heavyweight titles against former champion Hasim Rahman in Mannheim, Germany, on December 13.
Confirming the fight on his website, Klitschko said: "Hasim Rahman is a very strong and experienced opponent who I definitely won't be underestimating."
Rahman, who will be 36 when the fight takes place, knocked out Britain's Lennox Lewis to win the world title in 2001, but was in turn knocked out by Lewis in a rematch later that year.
Wladimir Klitschko, 32, had been looking for a replacement after Russian mandatory challenger Alexander Povetkin pulled out with an injury he suffered during a training session in his home town Kursk.