Eva Mendes shows up for our interview in Los Angeles' Griffith Park with Hugo, her rather intimidating Malinois (a Belgian variant of the German shepherd). We were supposed to take him for a walk, but a wintry drizzle has scuttled our plans — good thing, since Hugo doesn't look like he takes well to journalists. "Couchez!" she orders him sternly. Hugo immediately lies down. "It sounds so pretentious," Mendes admits, "but he learned his commands in French." Cesar Millan, better known as the Dog Whisperer, sometimes dog-sits Hugo, she informs me. Hugo also wears a behavior-modification collar, which Mendes controls with a beeper. Yikes — no sudden moves, I tell myself.

Mendes, 37, has always bristled at the expectation that in order to promote her latest film she must divulge tasty morsels of her personal life. Yet even someone as ferociously beautiful as Eva Mendes can't change the natural order of things in Hollywood. So here she is, cradling a paper cup of coffee with both hands as we talk about her latest effort, Girl in Progress, an art-house indie in which she plays a single mom so wrapped up in her own life that she fails to see that her chess-champ teenager is turning into a party girl. "She's a disaster, a mess, which I really love," Mendes says of her character.

Girl in Progress is a decidedly different turn for Mendes, who, for most of her 13-year career, has played the other woman: either the husband-baiting mistress (The Women) or the ass-kicking mantrap (Ghost Rider). In addition to her gigs as spokeswoman for Pantene and Thierry Mugler's Angel fragrance, she's a regular on every Maxim-esque Hollywood Hot List, thanks in no small measure to her nude romp in 2001's Training Day. "I have taken the opportunities that have come my way and made the best of them," Mendes says unapologetically.

Recently, she has taken on edgier roles, like the drug-snorting call girl in The Bad Lieutenant: Port of Call New Orleans and the delinquent mom in Girl in Progress. While Girl opens with her shimmying around her bedroom in a full slip la Elizabeth Taylor in Butterfield 8, for the remaining two hours she's far less appealing as a neglectful, narcissistic mother who makes one bad choice after another, careering toward disaster. Odds are good you've never seen Mendes quite so, well, unattractive. It's a first step, albeit a small one, in transforming a big-screen sex symbol to respected actress on par with, say, Julianne Moore and Annette Bening, her idols. "I have a girl crush on them," Mendes admits. "I'd kill to have half the careers they've had after 40."

Mendes' aversion to the press may be standing in her own way: The moviegoing public doesn't know a hell of a lot about her — and it's hard to root for someone you're not invested in. Until recently, she was a rarity in the weekly glossies, save for her stunning forays on the red carpet. (She is a favorite of top designers like Oscar de la Renta, Stella McCartney, and Versace, among others.) The press scarcely reported her eight-year relationship with Peruvian filmmaker George Augusto until the pair split in 2010. She is an actress who happily admits that she deals with her personal issues in the privacy of a therapist's office, not in the public arena of gossip columns. Boundaries, she says, are "necessary not just to be a celebrity, but to be a healthy individual."

Read the rest in the March 2012 issue of Marie Claire!

ALL ABOUT EVA: THE SEX SYMBOL SHARES HER STYLE SECRETS

Workout: "I run four to five times a week, mixing it up among distance running, intervals on a track, and running uphill on a treadmill."

Diet: "I don't eat meat and stopped eating chicken — my skin has gotten a lot better."

Go-to outfit: "I'm not a big jeans girl. Usually when I go out, it'll be in a dress — something floral or ultrafeminine."

Hair: "I have big, wavy, crazy hair, so it works best for me when I let it be. Here's a trick I learned from my mother: If your hair is a little greasy and you don't have the time to shampoo, put some baby powder at the roots and at the ends. It gives you that '70s textured look."

Beauty: "I like Dr. Perricone products, which have a minimum of ingredients and really work. I also use Laura Mercier's moisturizing foundation and eyeshadows. I'm not a fan of red lipstick — I go for anything peachy or pinky."

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