Singer Justin Timberlake is tipped to replace Simon Cowell as an American Idol judge.

Cowell quit the show in May to focus on his new US series The X Factor, which premieres in September 2011.

According to reports, American Idol producer Simon Fuller and Fox Network executives are also considering dumping the entire judges panel - which would mean booting songwriter Kara DioGuardi and renegotiating multi-year contracts with Randy Jackson and Ellen DeGeneres, reports contactmusic.com. 

American Idol bosses have insisted no decision is imminent, but insiders expect the new judge to be named in September this year.