Kristen Stewart explains her unsmiling expression

LOS ANGELES, Aug. 7 (UPI) -- Kristen Stewart is not a smiler and she doesn't care if people like it or not.

The Twilight star, 24, who is known for her serious manner both on and off the red carpet, spoke out about her unsmiling ways while interviewing for the September issue of Elle magazine.

"Now I feel like if I smiled for a paparazzi photo -- not that I ever would -- that's exactly what people would be desecrating me for," the actress said. "They'd be like, 'now you're going to give it up, now you're a sellout.' Like, okay. What do you want? What would you like?"

Stewart, who fittingly isn't smiling on the magazine's cover photo, also discussed her rise to stardom following the release of the first Twilight movie in 2008.

"The day the movie came out there was a picture of me -- in the New York Post," she recalled. "I was sitting on my front porch, smoking a pipe with my ex-boyfriend [Michael Angarano] and dog. And I was like, 'Oh shit, well, I have to be aware of that.'"

In time, the Snow White and The Huntsman star learned her way around Hollywood and is now rarely photographed by paparazzi. Stewart admits, however, that planning for the future is not something she engages in often.

"As soon as you start thinking about your career as a trajectory -- like, as if you're going to miss out on some wave or momentum -- then you're never doing anything for yourself anyway," she said. "Then you're truly, actually, specifically working for the public. You're turning yourself into a bag of chips."

You can check out Stewart's full interview and her grocery store-based photo spread when the September issue of Elle hits stands on Aug. 12.

Kristen Stewart