NEW YORK — Mandy Moore has a confession to make: She is a huge fan of TV’s hit reality show American Idol.

"I’m not going to lie. I’m a fan of the show. I watch it every week. I TiVo it. That’s how big a fan I am," Moore says.

The pop diva is being a bit sheepish in her admission because she helps filmmaker Paul Weitz skewer American Idol in his biting satire American Dreamz, which opens Friday.

Moore plays Sally Kendoo, a finalist on the latest season of American Dreamz, the most popular TV talent show in America.

Sally may have the wholesome girl-next-door look but, according to Weitz, who wrote and directed the comedy, Sally "is basically a sociopath. She so desperately wants to be a star, she’ll do anything to make that dream come true."

Weitz says he wrote the part of Sally with Moore in mind believing that "Mandy actually could win American Dreamz. She has the talent. She has the look."

He also felt casting Moore would provide the film with the irony it needed in this character.

"There’s something inherently sweet about Mandy; it makes it all the more interesting to see her in a villainess role," he says.

Even Moore surprised herself with the degree of evil she was able to conjure for Sally.

"I don’t know anyone like the Sally I created for American Dreamz," she says. "Jeeze Louise, no."

Weitz recalls he simply told Moore to "fantasize what it’s like to be nasty.

"I knew Mandy could do it because the genuinely nicest actors are the best at being nasty."

Unlike the winning contestants of American Idol, who become pop stars overnight, Moore, 21, had to pay her dues.

In 1999, at the age of 14, Moore was signed to a deal with Sony Records and sent on tour with the Backstreet Boys.

But when the label’s attempts to market her as the pop princess successor to Britney Spears, Christina Aguilera and Jessica Simpson faltered, Sony dropped Moore in 2004.

Still, she continued to record before concentrating more on her film career with such films as A Walk to Remember, How to Deal, Chasing Liberty and Saved!.

"I would never discredit anyone who is working their way up on a show like American Idol," she says. "I think they work so hard overcoming so many obstacles just to get on the show in the first place.

"Then, every week, they are judged in front of all of America. All that pressure must be overwhelming. I give them credit for getting up on the stage."

Moore insists she "would crumble under that kind of pressure, so I think they deserve all of the success that they get."

American Dreamz taps into the fascination with reality TV shows. Moore feels these shows are "like sporting events without actual athletes.

"People who aren’t into sports can tune in every week and vote to keep their people in the playoffs and, hopefully, get them into the final."

In an interview two years ago, Moore said she was considering putting an end date on her entertainment career to do something entirely different. She insists she didn’t mean she was setting a definite retirement date for herself.

"I think what I meant was that I only want to be doing this as long as I want to be doing this," she says. "I don’t want to have to be doing it."

She adds, "When the day comes that I’m done with the acting and singing thing then I will pack it in and go home. When it’s no longer satisfying and exciting, I’ll put it behind me.

"I’m 21. I don’t see that happening any day soon."

Moore has already completed the romantic drama Because I Said So with Diane Keaton and the wild sci-fi comedy Southland Tales with The Rock, Seann William Scott and Sarah Michelle Gellar. And she is filming the romantic comedy Dedication with Billy Crudup.

Moore’s private life came under unwanted scrutiny recently when actor Wilmer Valderrama appeared on The Howard Stern Show and detailed his amorous past.

He recalled he and Moore dated for 18 months between 2000 and 2002, claiming they were each other’s first loves, the implication being they lost their virginities to each other.

She would have been 16 or 17, and he would have been 20 or 21.

Moore has refused to comment on the stories.

While she was filming How to Deal in Toronto in 2002, she met and began dating tennis star Andy Roddick. They were together for 16 months but spent little time together. She recalls her schedule "was far too hectic for a relationship to work."

In 2004, she began dating Scrubs star Zach Braff, but both have slammed the rumours they are engaged.