Actresses Kate Mara, Elizabeth Banks, olympic gymnast Nastia Liukin, and tennis player Maria Sharapova attend the Peter Som Spring 2009 fashion show during Mercedes-Benz Fashion Week at The Promenade, Bryant Park on September 8, 2008 in New York City. (Getty Images North America | Andrew H. Walker)

NEW YORK — Some celebrities are content to be spectators at fashion shows; others want to be involved in the action on the runway.

Count Renee Zellweger in the audience camp and Justin Timberlake in the design category.

Zellweger, her hair swept neatly back and wearing a simple sheath, smiled as she watched Carolina Herrera's ruffled dresses and tiered silk gowns floated down the runway Monday morning at the Bryant Park tents as Fashion Week action for spring 2009 unfolded.

The night before, Justin Timberlake took over the Roseland Ballroom to showcase his William Rast collection for men and women.

Renee Zellweger attends the Carolina Herrera show on September 8, 2008 in New York. (Getty Images North America | Andrew H. Walker)

The musician, actor and now "creative director" designer created a short film in which he portrays William Rast, a southern boy on the run with his girlfriend, played by model Erin Wasson. More ads/webisodes (williamrastmovie.com) are to come chronicling the adventures of the duo, who can best be described as Bonnie and Clyde meet the rockabilly-grunge scene.

Models emerged from a log cabin complete with porch, autumn leaves and mounted elk head, and swaggered down the runway wearing ripped and tattered jeans, plaid shirts, leather jackets and studded vests. Among the accesories were fringed ankle boots for the women.

Taken individually, some of the pieces were wearable, such as the men's tuxedo jackets with squared lapels. Timberlake wore one Friday night to the Fashion Rocks concert here.

Among the other celebrity sightings at the fashion shows Monday were diminutive gymnast Nastia Liukin side by side with the Amazon-esque tennis player Maria Sharapova at Peter Som. And at Jill Stuart's show at Astor Hall in the New York Public Library, the front row held Bette Midler, Michelle Trachtenberg, and in true Fashion Week style, an actress who plays a fashion designer on TV, Lindsay Price of "Lipstick Jungle."

Justin Timberlake, left, and Trace Ayala acknowledge the audience after the William Rast spring 2009 collection show during Fashion Week Sunday, Sept. 7, 2008 in New York. (AP | Jason De Crow)