The 22-year-old actress plays the sexually adventurous first wife of Dean Moriarty, (Garrett Hedlund) in the big screen version of Jack Kerouac's classic novel and although Kristen knew she would have some racy scenes, she and Garrett weren’t expecting her to have to strip off so soon after she started shooting.

Garrett – whose character attempts a threesome with Kristen’s and Sam Riley’s (Sal Paradise) – told E! News: “Our first day of shooting was answering the door naked and her being in bed over there.”

Kristen added: “That was maybe the one day I didn’t feel as free as I did.”

However, despite her initial shock, Kristen admitted she was surprisingly comfortable with the sex scenes and is shocked with her performance when she watches the movie at premieres and screenings.

She explained: “I genuinely did feel so completely comfortable that watching it now even I’m like ‘Whoa!’ Which is fine, that’s the way I should react to it. I’m so not like her, as I’ve said.”

Here's the trailer -