Twilight actor Kristen Stewart has certainly come a long way from playing Bella Swan. She plays a Guantanamo Bay Marine guard in her new film Camp X-Ray, which was recently premiered at the Sundance Film Festival.

She reportedly took training from real marine guards for the same. The petite Stewart also says she found common ground between herself and the character of of Pvt. Amy Cole.

The movie is a fictional story about a friendship that develops between a prison guard and a suspected terrorist imprisoned on the U.S. Naval base since shortly after Sept. 11, 2001.

"She had aspects that I have and that I really felt," Stewart said about her character.

She also elaborated her challenges in playing a character which was so much in contrast to her playing a teenager in love with a vampire in the Twilight series.

"I forgot how to turn left. I was constantly rotating. Rehearsal was very necessary. Luckily there's a lot of material [for research]. There are multiple documentaries we watched. There were memoirs written on both sides of the coin. And then I hung out with this really awesome Marine for three days and learned things in a very accelerated way," Stewart confessed.

She also added that she was even taught how to stand and walk like a Marine.

"I spent a few days with a couple of Marines that really put me through the ringer. It was awesome. They're great guys. We wanted to represent them in the best possible way we can and if I was remotely unauthentic, I would die. I would hate that. We did everything we could to keep it real," Steward told E Online.

"He literally showed me how to walk. It's not like a physically strenuous role, but it should be clear I have training -- even though I just walk around in circles," Stewart explained.

Apart from the physical needs the character of the guard demanded, she also stated that she had to get into the psyche of the character she was playing.

"What was important to me was figuring out who she was," Stewart told USA Today