Back in January, people at the Sundance Film Festival got to see another daring performance from Kristen Stewart, this time playing a soldier stationed in Guantanamo Bay for a movie called "Camp X-Ray."

Now, the rest of the world gets to see what everyone in Park City, Utah was talking about.

In the film, Stewart plays Cole, a Gitmo guard who gets too close to one of its detainees (Peyman Maadi).

When we spoke with Stewart at Sundance, she shared her concerns that the audience wouldn't believe her in a military uniform.

"I was so nervous when I first started working and preparing because I didn't think that people would believe me or think that I looked tough in a uniform," she said, "that I could do that job, that I could wrangle detainees that are massive and scary."

"Camp X-Ray" opens in theaters on October 17.