Wladimir Klitschko and Samuel Peter last fought in 2005
Wladimir Klitschko will defend his IBF, WBO and IBO heavyweight titles against Nigeria's Samuel Peter in Frankfurt.
Klitschko, 34, will fight Peter on 11 September having been originally scheduled to meet Alexander Povetkin.
But after Povetkin failed to appear at a news conference in July to promote the fight Klitschko's camp opted for a rematch against 29-year-old Peter.
Klitschko said his fight against Peter in 2005, which he won on points, was "one of the hardest of my career".
Peter, nicknamed 'the Nigerian Nightmare', sent Klitschko to the canvas three times before losing a unanimous points decision to the Ukrainian.
Klitschko has 54 victories from 57 fights, while Peter is 34-3.
Peter also lost to Wladimir's brother Vitali in 2008, who is set to defend his WBC title against Shannon Briggs on 16 October.
The winner of either fight could face Britain's WBA heavyweight champion David Haye in 2011, with the Brit now likely have to wait until next year before he can meet one of the Ukrainian brothers if they are victorious.
The developments this week also leave Haye searching for a viable opponent this year for what would only be the second defence of his world title.
Having won the title against Nikolay Valuev in November 2009 Haye has only made one defence and has been left frustrated in his attempts to secure fights against either of the Klitschko brothers.
Fellow Londoner Audley Harrison is an option for Haye as is Poland's former cruiserweight champion Tomasz Adamek.
But with Haye vowing to retire before his 31st birthday next October, time is running out for the Londoner to keep alive his dream of unifying the heavyweight division.