J-Lo expected to replace Ellen on American Idol

Ellen DeGeneres is leaving American Idol after one season - and Jennifer Lopez is poised to step in.

J-Lo is close to signing a deal to join Fox TV's hit singing contest as a judge, according to a source.

The actor-singer-dancer, whose films include Selena and The Back-Up Plan, has appeared as a mentor on American Idol.

Ellen announced she is leaving the show after one season, following fellow judge Simon Cowell out of the door. Fox has yet to announce a replacement for Simon.

"A couple of months ago, I let Fox and the American Idol producers know that this didn't feel like the right fit for me," Ellen said in a statement.

The comedian-talk show host said she realised that while she 'loved discovering, supporting and nurturing young talent, it was hard for me to judge people and sometimes hurt their feelings'.

Ellen said she told the network she would delay any action until it had time to 'figure out where they wanted to take the panel next'.

Kara DioGuardi, who was added to the judging panel two years ago, is not under contract for next year and Fox has not announced whether she'll return.

American Idol was the US's favourite programme last season, the seventh time it has held that position. But it showed rare vulnerability, beaten in the weekly ratings several times by ABC's Dancing With The Stars.

A total of 24.2 million viewers watched the ninth season's final duel between Lee DeWyze and Crystal Bowersox, compared to the nearly 29 million viewers who saw Kris Allen win over Adam Lambert last year.