She's two parts Madonna, two parts Julia Roberts and one part Princess Di, with the body of Sophia Loren and the charm of Grace Kelly.

If that sounds way too good to be true, it is -- sort of.

The blond bombshell star of Simone, a satirical comedy about a digitally created movie star, is listed in the film's credits as being played by "herself."

"I'm no more artificial than anyone else in Hollywood," says Simone on her Web site, which features a filmography, a gallery of magazine covers and a naked picture of herself.

Good point -- but even she is fake. Simone is, in the playful double-speak of the film's writer-director Andrew Niccol, "a simulated simulation."

The creation of Simone -- think Sim(ulation) One -- is an elaborate promotional ruse by the studio New Line to promote the idea that their film stars the world's first realistic "synthespian," or computer-generated actor.

In fact, while writer-director Andrew Niccol (The Truman Show, Gattaca) originally toyed with that idea, sparking a squall of protest from the Screen Actors Guild, he decided that artificially creating an actress was prohibitively expensive. 

And so the face (and body) of Simone belong to an unknown Canadian model named Rachel Roberts. 

"All of the shots of Simone are doctored in some way, so it's always a combination of pixels and flesh and blood that you see," explains Niccol. 

Simone, out Friday, is the story of a has-been movie producer (Al Pacino) who resorts to using a digital replacement when his temperamental star (Winona Ryder) walks out in the middle of filming. 

The virtual actress becomes an overnight sensation, forcing Pacino to struggle to maintain the fiction that she's real as her public clamors for her presence at awards shows and press conferences.

Life is now imitating art -- with New Line trying to maintain the fiction that Simone is fake by not allowing Roberts to do interviews or be photographed -- and putting gag orders on her co-stars.

"I'm not allowed to say anything about anything any more," Pacino joked recently.

"It's a logical extension of the film," says Niccol, defending the studio's decision. "Is she a real fake or a fake fake?"

Niccol says his movie is meant as an affectionate dig at Hollywood and at "us, the audience, because we celebrate celebrities to such a degree.

"They're packaged and styled and have canned answers to talk-show questions -- we might as well worship a fake celebrity as a real celebrity."

All this talk of synthetic replacements may make the Tom Cruises and Meg Ryans nervous -- but it's too early for them to push the panic button just yet.

The current technology allows the creation of semi-plausible humans, such as the heroine of last year's Final Fantasy, but it's still years away from creating totally photorealistic actors.

"It's still far easier to cast an actor than create one," Niccol says.

It took a team of 10 to 15 special effects technicians six months of painstaking post-production to assemble Simone from the images provided by real-life model Roberts.

"But the day will come when you'll turn on the TV or watch a movie and not know who's real and who's fake," says Niccol. "And you won't care."

Not so fast, says Pacino.

"I can't see how a created, virtual actor could replace a real one," he says. "There's a viable human interchange between the audience and an actor that you can feel.;

"At least I want them to really be there."

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