Kristen Stewart is known for her poker face on the red carpet, rarely opting to flash a smile as she poses for photos. But, the reason behind her bad attitude might be explained in a new interview with Marie Claire U.K., in which she reveals she's a very unhappy person.

“I’m a miserable c---,” she admitted during an interview with Balenciaga creative director Nicolas Ghesquière for the magazine. “I’m not sure if I’m most happy when I’m comfortable and content or when I’m pushing myself to the limits.”

“There are such different versions of happy," she continued, "And I really appreciate both.”

Lately, the 22-year-old "Twilight" star has seemed depressed after photos surfaced in July of her cheating on her boyfriend, Robert Pattinson, with her married "Snow White and the Huntsman" director, 41-year-old Rupert Sanders. But, the media scrutiny comes with being an actress in Hollywood, and there's no denying Stewart loves her job.

As for what she'd be doing if she wasn't starring in hit movies, Stewart revealed, "I’d probably go back to school, read a lot and figure out what I should do."

What do you think of KStew's comments about her unhappiness?