Olivia Wilde has shaken off her ''bad ass'' reputation for her new role in 'Drinking Buddies'.

The 29-year-old actress was thrilled to be cast in the romantic comedy - in which she plays Kate, a young brewery owner alongside New Girl's Jake Johnson - as it allowed her to break away from her usual parts.

Olivia - who recently announced she is expecting her first child with her husband actor Jason Sudeikis - claims she was instantly typecast after appearing as bisexual bar owner Alex in teen drama 'The O.C.'.

She said: ''I got cast in 'The O.C.' and even initially in 'House' as a very icy, confident, emotionally reserved woman, which is not me. I can't really analyse why. People thought I could only play the bad ass so I'd always got those roles.''

She added: ''It just doesn't feel very human. People saw I could do it but it takes more courage to play someone vulnerable.''

Despite a number of high-profile roles - including a five-year stint on medical drama 'House' and a part in the new blockbuster 'Rush' with Chris Hemsworth - Olivia says 'Drinking Buddies' is one of her only films she'd recommend people watch and she credits director Joe Swanberg for creating such a great movie.

In an interview with The Guardian newspaper, she said: ''I feel it's the first time I've hit a real nerve. It's the only film of mine that I'd tell people, 'Please, please see it!' I think it's a really honest piece of work ... There was no script! Nothing was written down. I never got so much as a piece of paper. You improvise to find out what the scene is about. Then you start again, but you reach the point sooner ... It feels like the first time I've been able to loosen up and let it go.''