Olivia Wilde volunteered to appear naked in her new movie.

The 'Drinking Buddies' star, who is engaged to Jason Sudeikis, claims it was her idea to strip off her clothes for a drunken bonfire scene in the film, which was based on a real bash that the crew had on a beach at Lake Michigan.

The 29-year-old actress told the Chicago Sun Times' Sunday magazine Splash: ''So the next night we did the bonfire scene and I thought, 'I should probably go skinny dipping.' And I ran into the water, and I didn't know what Jake [Johnson] was going to do! If he follows me into the water, we'll shoot something in the water. Or he doesn't. But I'm just as present in the scene as the audience is, which was really fun. And Chicago is home to some of the world's greatest improvisers, so it felt appropriate that we were making the film there.''

Olivia recently revealed that she can't wait to turn 30 next March and no longer feels pressure to be a huge success in Hollywood.

She said: ''The 20s are awful! It's like high school all over again!

''It's so hard, it's so bumpy. It's like you're on this really bumpy dirt road and you're hitting all these rocks and then you suddenly hit the highway and you're like, ah! Smooth!

''At one point I was doing seven movies a year, and that spoke to a lot of how I was feeling in my actual life. Twenties panic. Just go, go, go.''