Olivia Wilde on Going Nude in 'Cowboys & Aliens,' 'The Change-Up'

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The actress says she didn't even know she had revealed her backside in one of the movies until people started asking her about it.

Olivia Wilde bares a little more than just her soul in not one but two upcoming movies.

The actress reveals her backside in the Cowboys & Aliens, opposite Daniel Craig and Harrison Ford, and in The Change-Up, which stars Ryan Reynolds and Jason Bateman.

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“There’s a little nudity in this one," Wilde told Access Hollywood of Cowboys, adding, “I feel like if I feel really safe and if I feel like the story calls for it, then I’m not so shy.”

But in Change-Up, Wilde said she didn't even realize her rear end was being shown until people who had seen the movie started asking her about it.

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“With The Change-Up I didn’t really realize that’s what was happening, as if I didn’t really know where the camera was," she said. "So then people saw the movie and they’re like, ‘You know your butt’s in the movie?’ and I was like, ‘What?’ I had no idea! But you know, I think when you agree to do a movie, like that you have to go 100 percent for it.”

Cowboys & Aliens, a genre-defying mashup of a Western and space-invasion movie directed by Jon Favreau (Iron Man), opens Friday. The movie had its premiere at Comic-Con on Saturday night.

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Change-Up, a body-switching comedy from David Dobkin (Wedding Crashers), opens Aug. 5.

Wilde also has appeared in the TV series House and last year's Tron: Legacy.