BERLIN (AFP) - Double world heavyweight champion Vladimir Klitschko will defend his WBO belt against American Tony Thompson on July 12 in Hamburg, Germany, it was confirmed here on Tuesday.

Thompson, 36, has 31 victories, 19 knock-outs and one defeat to make him the number-one WBO heavyweight challenger.

He will meet the 32-year-old champion at Hamburg's Color Line Arena this summer.

Klitschko still needs clearance for the Thompson fight from the IBF board in New Jersey because their official challenger is Russian Alexander Povetkin, who will face the Ukrainian at the end of the year or early 2009.

Klitschko unified the WBO and IBF titles when he beat Russian fighter Sultan Ibragimov last February in Madison Square Garden, New York.

Povetkin, 28, is Klitschko's official IBF challenger and the 2004 Olympic heavyweight champion is unbeaten since turning pro with 15 victories and 11 knock-outs.

Klitschko has 50 professional wins with 44 knock-outs and three defeats.