Olivia Wilde’s television and movie roles couldn’t be more diverse. She has played a club manager on The O.C., a doctor on House and an “isomorphic algorithm” in Tron: Legacy. But with the exception of the Tron role, in which Wilde sported a futuristic asymmetrical black bob, her characters always seem to have the same hairstyle: long and natural.

In real life, Wilde, who appears in this summer’s People Like Us, has worn her thick, slightly wavy tresses both above and below her shoulders; she’s changed her color and played with her bangs. But as with her on-screen looks, the overall effect doesn’t really change. Her hair has a certain trademark style. It’s natural, earthy and fuss-free—“the new bohemian look,” says Los Angeles–based celebrity stylist David Babaii, who has worked with the actress for more than a year.

Trademark hair is a convenient tool. A familiar cut that looks great on you is one less thing to think about when you’re putting yourself together. If you’re searching for your own signature, Babaii recom- mends trying on different styles—literally—at a wig store. Experiment. See what looks best and makes you feel comfortable. “Think of it like a first kiss: you know instantly if it is good or bad,” says Babaii, whose clients include Kate Hudson, Angelina Jolie and Blake Lively.

“She has a great personality

that lets her carry any look.”

- David Babaii

The downside of a signature style is that it can turn into a rut, and that’s where simple switches can help. Back in January, ready for a change, Wilde had Babaii cut off several inches of her then brown hair, transforming it into a long bob with strong bangs. These days she’s growing the bangs longer.

The color is getting lighter too. “Hair color is also a way to make a change,” Babaii says, and Wilde is proof. A natural blonde, she has also been a dark brunette.

Because her cut is always very precise, Wilde can just wash it and go, but she can also wear it stick straight or in loose waves, in tendril-ly updos and cinched ponytails. Not surprisingly, it all looks good.

“Olivia has such great hair and such a beautiful face that anything would complement her,” Babaii says. “She is fun-loving and has a great personality that lets her carry any look.”