"I have a couple pairs of ridiculous underwear that I'll never wear again," Stewart laughed during her interview with HitFix, noting that her set pieces and costumes from "Welcome to the Rileys" bordered on the unusually seedy.
The young actress stars as Mallory, a teenaged runaway who works as a stripper and turns tricks in New Orleans to scrape by. Her laugh-it-off toughness is countered by Doug (James Gandolfini) and Lois (Melissa Leo) -- a married couple who'd lost their daughter in a car wreck -- suddenly propelled into her hard-knock life.
It's not a life, on paper, to which Stewart could easily relate, but when it came time for certain scenes to shoot, things got "incredibly real."
One of those was shot outside of a motel, after one of Mallory's "clients" takes off with the bulk of her money and she's forced to call Doug for help. "As much as [Mallory's] used to that line of work, I cannot relate to that at all," Stewart said. "I was scared that I was gonna do an impression of something instead of going through it."
Stewart also stepped outside of her usual skin as Joan Jett in "The Runaways," which premiered at the same time earlier this year as "Rileys" at the 2010 Sundance Film Festival. She was caught busily promoting both films, which was more of a relief than a major working stress.
That excitement grows, now, as Rileys goes wide to theaters, and Stewart's fans from "The Twilight Saga" see a very different side of Stewart's Bella Swan.
"It's funny to me... that people are like, 'Oh my gosh, she's in a stripper movie,'" she explains. The two-part and final stretch in the vampiric series "Breaking Dawn" has just begun production. "I figure that people expect that from actors, that they want to do different stuff. I totally acknowledge that I am so very tied into the whole 'Twilight' thing and a lot of people -- that's all they've ever seen of me."
"Welcome to the Rileys" is out on Oct. 25.
Follow HitFix’s Katie Hasty on Twitter for more music and movie news at /katieaprincess.