Aclone army of starlets marches through Hollywood casting offices every day — all beautiful, all talented, all interchangeable. Pick one, any one. But every so often a young actress rolls into town and drops jaws. Keep your eye on that one, studio executives say. That one is different.

Olivia Wilde, 27, is one of those women.

The green-eyed bombshell arrived in the movie capital in 2002, strangely enough, to work in a casting agency. Her parents, two prominent Washington journalists with all sorts of Beltway and celebrity connections, helped arrange it. The goal, according to her mother, Leslie Cockburn, a producer for 60 Minutes, was to squelch Wilde’s interest in acting by exposing her to a particularly hardhearted corner of the dream factory, where hundreds of résumés are casually tossed aside.

“They thought I would take one look at the cattiness and people from Yale and Juilliard begging for jobs and hightail it out of town,” Wilde said recently over lunch at a tucked-away little cafe on Sunset Boulevard.

But Wilde was almost immediately cast herself, popping up in shows like The OC on Fox and landing a continuing supporting role on that network’s hit series House as a self-destructive doctor. Her first big movie part, a Joan of Arc-like cyber warrior, came last year in Tron: Legacy. Now she has seven films in stages of completion, starting with Cowboys & Aliens, an atypical action extravaganza that arrives on Friday from Universal Pictures.

“Olivia reminds me a lot of Angelina Jolie — a fiercely intelligent, drop-dead gorgeous woman who knows what she wants to do and goes after it,” said Donna Langley, Universal’s co-chairwoman.

Despite her success in landing ensemble movies Wilde is still waiting for that one breakout leading part, either a dramatic role that gets her noticed by critics or one that makes her the face of the film. Her looks could prove a liability; when you are the kind of actress who lands the No. 1 spot on Maxim magazine’s Hot 100 list, it’s very easy to be pigeonholed as cinematic eye candy. It took Charlize Theron’s turn as a greasy-haired, yellow-toothed serial killer in Monster for people to take her seriously.

Wilde has also chosen a difficult balancing act, at least for a starlet: She has ideas, and she expects directors and writers to listen to them, at a time when up-and-coming actresses of her ilk are still expected to be seen and not heard. When they do speak up, especially publicly, studios often deem them “difficult” and they wither. See: Heigl, Katherine, or Fox, Megan.

“Trying to fight this industry’s tendency to celebrate the physical is a waste of time,” Wilde said. “So I’m happy to play that game. But I am also thirsty for input. I’m not a dunce whose only skill is knowing how to take a photograph, you know? And at the end of the day I think it makes me slightly less replaceable.”

When she was cast in Cowboys & Aliens as a gunslinger with a big secret, the writers of Tron: Legacy, Edward Kitsis and Adam Horowitz, called the new film’s writers with a warning: Wilde will want to discuss her character’s psychological makeup aggressively. “It wasn’t a negative, but rather saying that she’s a dream, somebody who is collaborative and can talk intelligently about the story,” Horowitz said.

In The Change-Up, which stars Jason Bateman and Ryan Reynolds as opposites who swap bodies Freaky Friday style, Wilde, who plays a vixen legal assistant, spoke up with an idea about adding a scene where her character gets a tattoo in, um, an extremely delicate spot. It’s in the finished movie (although her parents may want to close their eyes during it).

“What makes Olivia’s input different is that she’s not a squeaky wheel who rolls onto the set and has this pushiness that demolishes the whole thing,” Bateman said. “She has a self-deprecating sense of humour about herself, and she’s generous with ideas, even if they don’t directly benefit her.”

In person Wilde is warm and chatty, with perfect posture. An aura of self-confidence surrounds her, tempered slightly by a tendency to bite her lower lip. She arrived at lunch early, seemingly without makeup, and immediately started talking about her dog, Paco, a rescued cross-breed that has appeared in Old Navy commercials. After being trained by the retailer to perform in ads, Paco now enjoys wearing clothes, she said with a laugh.

Calling herself a “world-class nerd,” Wilde bemoaned a meeting later in the afternoon at the slick Los Angeles branch of the Soho House chain of private clubs. ”One of the things that takes you by surprise is that there is zero sense of entitlement,” said Katie Jacobs, a House executive producer. “She considers herself as somebody who always has her foot in her mouth.”

As a child Wilde was a bit of a ham. “Olivia religiously watched reruns of I Love Lucy to study Lucille Ball’s technique,” Cockburn said, noting that her daughter also made elaborate home movies.

Because she was such a fan of slapstick humour — Wilde lists the Police Academy movies as childhood favourites — her parents took her to a taping of Saturday Night Live when she was 10, and they attended the after-party. Chris Farley noticed her and challenged her to a brownie-eating contest. “He won, but I gave him a run for his money,” Wilde said.

The Change-Up, directed by David Dobkin (Wedding Crashers), definitely has its slapstick moments, but her role in Cowboys & Aliens, which co-stars Daniel Craig and Harrison Ford, is serious and brooding. Wilde’s parade of films following those two are also diverse: in the indie comedy Butte, she plays a competitor at a butter-carving competition; Blackbird, a crime drama, finds her as a desperate fugitive; in the science-fiction thriller In Time, about people who stop ageing at 25, she plays Justin Timberlake’s mother.

Picking the widest variety of roles is partly a way for Wilde to show that she’s more than just a pretty face. To emulate the careers of Sigourney Weaver or Katharine Hepburn, two actresses Wilde said she sees as role models, she will need to win over critics. So far that crowd has been quiet on her acting, instead commenting mostly on her babe-dom.

But role diversity also reflects her wanderlust. She’s one of those people who casually peppers a conversation with sentences like “I was in Brazil, learning how to free-dive from some spear fisherman.”

That tendency to leap before she looks is evident in her personal life too. When Wilde was 19 she was engaged to Tao Ruspoli, a filmmaker and son of an Italian prince (for real), at the anything-goes Burning Man festival in Nevada. A few weeks later she married him on an old school bus, where he was living. She filed for divorce in March.

“It was a great eight years, but it was time for both of us to move on,” she said. At the least she came away with entertaining stories about visiting his family in Italy, like the time she arrived at a “casual” dinner to find trumpet players and people on stilts dropping flower petals. “I was like, where am I?” she said. A similar feeling came over her on the New Mexico set of Cowboys & Aliens. “I was coated in dust for four months straight,” she said. Not that she complained to Favreau, who said he was surprised to find her asking for harder and harder stunts.

He pointed to a scene in which Wilde’s character, on a horse galloping across the desert, is yanked from the saddle by a flying alien. The plan was to use a stunt double for part of the sequence, augmented by a computerised “digital double” in postproduction. All Favreau expected Wilde to do was ride a mechanical horse for a couple of close-ups of her face.

But Wilde ended up performing the complicated stunt herself, being pulled off a speeding horse by a wire attached to a crane. “Frankly, she put our stunt riders in a tough spot,” Favreau said. “Here was our ingénue, doing all of the scary stuff and making it look easy.”