'All American Girl' Contestants Sue Nigel Lythgoe for Sexual Assault, Battery

On the heels of Paula Abdul's lawsuit, veteran TV producer Nigel Lythgoe finds himself facing a second lawsuit, claiming he sexually assaulted and harassed 2 contestants 20 years ago on a reality competition show.

Both women were contestants on the show, "All American Girl" -- which aired for one season back in 2003 -- and Lythgoe was a producer on the program. According to the docs, obtained by TMZ, the women allege he would repeatedly show up on the set, and in dressing rooms, when they were wearing dance costumes ... and "openly swatted and groped" their butts.

In the suit, which the plaintiffs are filing as Jane Does, they say production hosted a party to celebrate the end of filming ... but at the end of the party, they claim Lythgoe insisted one of the women ride with him back to the studio where everyone else on the cast was going.

The second plaintiff insisted on going with them to protect her fellow contestant -- but they allege Lythgoe drove them back to his home, where he made sexual advances on both of them. In the suit, they allege he lifted up the sweater she was wearing, and "engulfed" one of the women while trying to kiss her ... and she immediately rejected him.

The other plaintiff claims he got aggressive with her by pushing her against a grand piano and forcing his mouth and tongue on her ... all of which she protested.

The women are suing Lythgoe and an unnamed production company for sexual assault and battery, sexual harassment, intentional infliction of emotional distress and negligence.

As we said, they've filed anonymously, and the suit only identifies the defendant as "John Roe N.L." and the show as "AAG" -- but TMZ has confirmed through sources with knowledge ... they're referring to Nigel Lythgoe and "All American Girl."

The plaintiffs cite California's Sexual Abuse and Cover Up Accountability Act ... which they believe allows for the revival of their claims even though the statute of limitations would have otherwise run.

TMZ broke the story ... Paula Abdul also cited that Act when she sued Lythgoe last week for allegedly sexually assaulting her while they were working together on "American Idol" and "So You Think You Can Dance."

Lythgoe called Paula's lawsuit "wholly untrue" -- adding the allegations are "deeply offensive to me and to everything I stand for."