Theo James drinks alcohol to help him prepare for ''really hard-core'' sex scenes.

The 30-year-old actor admits filming intimate moments can be very awkward and was relieved his tryst with Shailene Woodley in their new film 'Insurgent'' didn't need to be graphic.

The British star said: ''Sometimes booze helps if it's really hard-core. With this, it's OK, because at the end of the day it's going to be PG-13. Sometimes the most awkward thing is [when] you're shooting and you're doing something, and then something has to be tweaked, so you can't move, but you're right there. So you're like, 'What's up?' And you're completely naked, covered in sweat.''

While Theo finds sex scenes uncomfortable, Shailene, 23, doesn't mind stripping down on camera.

She told E! News: ''I don't know if it's necessarily confidence as much as just like we all have bodies under these clothes. I guess I'm very European in that way. Sexuality is a very normal part of life and the more we suppress that normalcy, I think the more we seek it in ways that don't actually fulfill our sexual needs.''

The brunette beauty also credits Theo for helping her to stay relaxed on set.

She said: ''The director creates a very safe environment where he's like only the keys need to be in that room. There are only maybe four people in there with you. And then if you're working with an actor who is a gentleman - or a gentlewoman, depending on the scene - then it's a very sort of technical experience. Theo is a gentleman...It was like we were doing any other scene, in a way.''