Wilde about Olivia

“You’re going to be so sick of me,” warns Olivia Wilde with a knowing smile.

The actress, best known for her role as resident hottie Thirteen on Fox’s “House” medical drama, is making her rounds on the big screen this summer. She plays the leading lady in the sci-fi westerner “Cowboys & Aliens,” which opened last week, followed by another key role in the adult comedy “The Change-Up,” which opens today.

“I feel very lucky to be in two such different movies,” said the 27-year-old with luminous green eyes. “I love that people don’t actually understand how it’s me in both of them. I look so different and act different – that’s obviously the goal of any actor.”

Wilde was last seen on the big screen starring alongside Jeff Bridges in the hit 2010 sci-fi sequel “Tron: Legacy.” She went from making Jon Favreau’s “Cowboys & Aliens,” an effects-laden sci-fi action adventure set in the Old West, to the contemporary suburban comedy “The Change-Up,” directed by veteran comedy helmer David Dobkin.

“I remember walking around this set of cowboys in this western town, holding the script for ‘The Change-Up,’ and laughing,” she recalled. “Everybody told me if a script makes you laugh that hard, you can’t miss the opportunity.”

In the 1875-set “Cowboys & Aliens,” she plays Ella, an elusive traveler who helps Daniel Craig’s gunslinger hero round up an unlikely posse of bitter enemies to fend off an army of mysterious attackers from another world.

Although Wilde had prior experience in the sci-fi genre, having played a lifelike computer program in “Tron: Legacy,” she was less versed in the adult-comedy arena for “The Change-Up.” She said she relished the opportunity to make a raunchy comedy aimed squarely at adults.

“Out of the bunch, I was the least experienced in this type of film,” she admitted, comparing herself with co-stars Ryan Reynolds and Jason Bateman. She credits Dobkin for seeing something in her prior work that made him confident about casting her.

In “The Change-Up,” she plays Sabrina, the sexy co-worker for whom Bateman’s married lawyer, Dave, has the hots. When Dave switches bodies with his best buddy, Mitch, a reckless man-child played by Reynolds, he’s finally free (in Reynolds’ body) to ask Sabrina on a date.

Wilde was confident from watching Dobkin’s other comedies, including 2005’s blockbuster “Wedding Crashers,” that she was in good hands.

“Seeing what he had done, particularly with Isla [Fisher’s oddball] character in that, I could see he respected and encouraged funny women,” she said.

A writer at heart, Wilde offered Dobkin some ideas to flesh out her character in the movie, and he welcomed them.

“Sabrina already was someone I really wanted to play – she was smart and interesting,” said the actress, “but she wasn’t necessarily as wild as she ended up being. We all worked together to make the [early] scenes at the office a little more of a misdirect for what happens later.”

The actress had others ideas. For example, she persuaded Dobkin not to make Sabrina Dave’s secretary but instead a fellow lawyer at the firm. Also, she conceived the idea about Sabrina and Dave (in Mitch’s body) getting tattoos on their adventurous date.