NEW YORK -- In January, Kristen Stewart premiered "Welcome to the Rileys" on a windswept mountainside in Utah during the Sundance Film Festival. Nine months later, in the considerably less picturesque but no less celebrity-filled environs of Manhattan's Tribeca district, Stewart was back to do it all over again.

At the Tribeca Grand hotel on Monday night, KStew shined in a short Valentino dress as she and her co-stars, James Gandolfini and Melissa Leo, were joined by celebs like Gerard Butler, Christina Hendricks, James Woods, Danny DeVito, Russell Simmons and Adam Duritz. They were all there to celebrate "Rileys," which hits theaters on October 29. The film tells the story of a [article id="1650274"]runaway-turned-stripper (Stewart)[/article] who's taken under the wing of a grieving salesman (Gandolfini). Stewart told MTV News at Sundance that she considered the role the most personal of her career.

"[It] sort of changes you and shapes you in a certain way," she said. All these months later, she admits that the part still sticks with her.

Director Jake Scott, too, has noticed a change in Stewart from when he worked with the actress back in 2008 on "Rileys." After all, the shoot took place before "Twilight" had even hit theaters. Stewart was only 18 then, thrilled to be taking on her first adult role, and unaware she'd soon become a household name. Years later, Scott only had to look down the red carpet at his lead actress to see her newfound maturity.

"She's grown up. She's a woman now," he told us, adding that she possessed the seeds of that maturity in October '08 when the "Rileys" production kicked off. "It was an act of courage on her part, especially when you consider she was just 18."

Check out everything we've got on "Welcome to the Rileys."

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