Wladimir Klitschko (Ukrainian: Володи́мир Володи́мирович Кличко́ [Volodymyr Volodymyrovych Klychko]; born 25 March 1976) is a Ukrainian heavyweight professional boxer.
Klitschko is the former Transnational Boxing Rankings Board, lineal, WBA (Super), IBF, WBO, IBO and The Ring world champion.
Klitschko was the longest reigning IBF, WBA, WBO & IBO heavyweight champion in history with the most title defenses for the IBF, WBO & IBO titles (23).
Klitschko's older brother is Vitali Klitschko. More: en.wikipedia.org.