Kristen Stewart wanted sex scenes

Los Angeles - Kristen Stewart "really wanted" to shoot the sex scenes in On the Road.

The 22-year-old actress was just 16 years old when she was cast as Marylou in the adaptation of Jack Kerouac's classic novel and she is relieved filming was delayed for a few years as she was at the "perfect" point in her life to tackle the role.

She said: "I was terrified of this part. I knew I was going to play Marylou since I was 16. And thank God I got to grow up a little bit, because I was a much younger 16 year old than LuAnne [Henderson, who the character is based on]. We made the movie when I was 20, the perfect point.

'Nothing to be ashamed of'

"But I love pushing, I love scaring myself. I really wanted to do the sex scenes. As long as you're being really honest there's nothing ever to be ashamed of."

While Kristen - who is best known for playing Bella Swan in The Twilight Saga franchise - says working on On the Road was just as "serious" as her efforts in the vampire film series, she admits her approaches to each differed because of the material she was working with.

She explained to website The Arts Desk: "Both were just as serious. I think the difference between the two adaptations was the approach to the script. In Twilight I was religiously obsessed with getting lines perfect, because I loved them, and I wanted them in a certain way and I knew that fans did as well, because I'm one of them.

"In On the Road my expectations are very similar to any Beat fan - you don't want something neatly packaged and contrived and delivered. A truer rendition of this book would be lines that were forgotten and rediscovered in the moment. You want to watch impulse, you want to watch people fall down and get up and not know what's gonna happen next."

Watch the On the Road trailer here: