Stars dressed down, shining bright at rehearsals

Robert Downey, Jr. Charlize Theron. Kathy Bates. John Travolta. Tina Fey. Matt Damon. Jake Gyllenhaal. Kate Winslet. Penelope Cruz. Tom Hanks. Jennifer Lopez. Robin Williams. Zoe Saldana. Sarah Jessica Parker.

There were so many stars inside the Kodak Theatre Saturday, it looked like a casual version of Oscar night.

Instead of the glamorous gowns and tuxedoes they'll wear for Sunday's big show, the stars were relaxed in jeans and sneakers. And instead of being live on the air in front of millions, they performed behind closed doors for a small crowd of show workers.

Damon wore a hooded sweat shirt and knit cap as he rehearsed, pausing from time to time to marvel at the show's stunning set.

Saldana wore skinny jeans and a sleeveless white blouse with towering purple platforms, and bobbed her head to the music playing as she practiced her presentation.

Travolta was in jeans and a ballcap, his credential tucked into his back pocket.

"Oh my God, it's tiny!" he said when he saw the size of the print on the teleprompter he was meant to read. Bates, in a paisley shawl and flats, had the same issue and producers bumped up the font size.

Downey chewed gum and playfully struck a pose during his brief rehearsal. Lopez looked glamorous in a super-short red minidress and tall spiked heels.

A bearded, bespectacled Williams came out in a black raincoat and cargo pants. Instead of opening the prop envelope, he held it against his forehead Johnny Carson-style and intuitively announced the winner.

"It's Sarah Palin, for 'I'm Still Here,'" Williams quipped, and the crowd of show workers roared.

Cruz was perfectly put together in a shiny black coat and matching high heels. Winslet, too, was radiant in a simple black jacket and jeans. Parker maintained her trademark style with a hot pink scarf around her neck and bright blue Louboutins on her feet.

A makeup-free Theron toted a coffee cup to her rehearsal. Wearing jeans and heels, her hair in a ponytail, she practiced her lines - keeping her dress in mind.

She chatted with a producer about camera angles, then said, "Well, I'm not wearing underwear."

"Too much information," a director's voice boomed over the loudspeaker.

The Oscar-winner laughed. "I didn't realize everyone could hear me," she said, before thanking the crew and waving goodbye.

The always affable Hanks, a two-time Oscar winner and Academy Awards regular, came to rehearsal in a blazer and jeans. His wife, Rita Wilson, sat on the side of the stage and checked her BlackBerry as he quickly ran through his lines.

On his way out, he greeted the producers and his academy colleagues.

"See you tomorrow," he said. "And good luck."