Credit: Dimitrios Kambouris/

It's happening, after all.

Jennifer Lopez's deal is set to become a judge on American Idol, an insider confirms to

Final contracts are currently being signed by Lopez -- plus Randy Jackson and fellow newcomer Steven Tyler, with an official announcement expected in early October, before auditions begin for the new season.

After a long negotiation process, "it ended up working out and they have a good agreement," the source tells Us.

The star's rep had no comment.

The insider adds that Lopez, 41, was selected as replacement for recently departed judge Kara DioGuardi -- not Ellen DeGeneres, who quit the show on her own accord.

Tell Us: will Jennifer make a good judge?