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

A person familiar with negotiations for Lopez said she is close to signing a deal to join Fox TV's hit singing contest as a judge.

The person spoke on condition of anonymity.

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

DeGeneres 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 Cowell.

"A couple months ago, I let Fox and the American Idol producers know that this didn't feel like the right fit for me," DeGeneres 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".

DeGeneres 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".