NEW YORK"Welcome to the Rileys" director Jake Scott has used phrases like "emotionally naked" and "got dirty" to describe Kristen Stewart's performance in the film. The 20-year-old actress plays a broken young woman thrust into a life of stripping in a seedy club and selling her body in fetid motel rooms.

At the film's red-carpet premiere in Tribeca on Monday night, Scott continued to hit on those same themes of unvarnished emotionality, comparing KStew to one of the most critically lauded and emotionally expressive actresses in Hollywood.

"That's like Meryl Streep stuff, you know?" he told MTV News.

He was speaking specifically about how Stewart took on such a demanding role at such a young age — and how she delivered such a top-notch performance. "I know that she put a lot of herself into that role," he said. "She was exposing herself emotionally. In order to do that, you have to put yourself there. It was an act of courage on her part, especially considering she was only 18."

Stewart's co-star, Melissa Leo, agreed, telling us how she and James Gandolfini watched in awe as KStew blossomed on the "Rileys" set. "I met Kristen at a very special time," she said. "She had just done 'Twilight.' She had been acting for a while. She has always carefully chosen her roles. Playing the character, she was acting for the first time as an emancipated actor. It was a treat for James and I to watch her spread her wings."

That's exactly what Scott was watching on the red carpet Monday, as Stewart strode confidently from interview to interview. "She's grown up," he said. "She's a woman now. She was a girl when I first met her. I've now known her probably three years. She's just becoming this wonderful woman."

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

For breaking news, celebrity columns, humor and more — updated around the clock — visit MTVMoviesBlog.com.