PARK CITY — Steven Soderbergh is famous for becoming famous at Sundance.

One day he was "a director" and then in the space of a couple of hours, after his film "Sex, Lies and Videotape" screened at Sundance in 1989, he became "director Steven Soderbergh." The film won both the audience award and the grand jury prize that year and went on to Golden Globe and Oscar nominations.

It helped put Sundance and independent film on the American landscape, and he has been visible all week in Park City to celebrate the festival's 25th anniversary.

So it was a surprise, if not a shock, when the festival veteran showed up Tuesday night for what the program called "Sneak Peek 2" at the Eccles Theater and he complained good naturedly that people had been telling him all week that they couldn't wait to see his film that nobody was supposed to know about. To the delight of the audience, there was a film and it was Soderbergh's project, "The Girlfriend Experience."

Far from the director's mainstream fare like the "Ocean's Eleven" trilogy or the Best Picture winner "Traffic" (which beat out his other nominee "Erin Brockovich" in 2000), this is a non-linear tale, which means parts of the ending are shown at the beginning while some cause-and-effect moments are saved until the end.

It was shot in 16 days for $1.7 million. It is experimental and far more tame than anybody can believe a story about the relationships and emotions of a high-priced escort and her boyfriend can be. Relying almost completely on dialog, he used the live-audience experiment to shape his own experience of the film.

"It is the first time showing this to an audience, and while watching I can feel things about it; the structure is very tricky," he said on stage after the conclusion of the film. The almost complete inexperience of the cast prompted him to shoot the film chronologically — unheard of in studio endeavors — and chop it and mix it around later.

"I cast this film based on character similarities," he said, explaining that the actors improvised each scene, after he gave them overviews, in one or two takes. "I tried to find a balance and play fair. We were working without a net but only four feet off the ground."

Sasha Grey is the only member of the cast with experience in front of the camera. He drew a big laugh when, after an audience member asked why Grey is nearly always eating while communicating, he admitted that in all earnestness, "I think eating on screen is always so interesting."

He stressed again to the audience that the film, which doesn't have a release date, is a work in progress and then tried to keep the screening hush-hush.

"Remember, you weren't here. This didn't happen," he said as he walked off stage to raucous applause. Sure, just like everybody "forgot" his first Sundance film.

E-mail: lc@desnews.com