Paula Abdul's departure from the show after she and "Idol" producers failed to agree on a new contract has left the fourth panelist's chair empty.
Katy Perry, whose appearance was previously announced but not scheduled, is also to help out this week, TVGuide.com said.
Other celebrity guest judges to appear on the show next season include Victoria Beckham, Mary J. Blige, Joe Jonas, Neil Patrick Harris and Kristin Chenoweth.
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