It stands her in great stead each week on ER, where she plays nurse Carol Hathaway to George Clooney's amorous surgeon Doug Ross.

Her former rough and tumble ways definitely came in handy last summer when she filmed the bank-robber saga The Newton Boys, playing the love interest of Matthew McConaughey.

"ER is a bit of a boys' club," explains Margulies. "There's never any shortage of testosterone. The same was true on the set of The Newton Boys. Between takes, we'd go to someone's trailer and there would be me with Matthew, Ethan Hawke, Vincent D'Onofrio, Skeet Ulrich and Dwight Yoakam.

"Some actresses would be distressed being so outnumbered all the time but it's never an issue for me. I was a real tomboy growing up.

"I never played with dolls and got footballs and baseball gloves for Christmas. All that changed when I reached puberty, but it's given me a better understanding of how guys think and bond."

Margulies says her male co-stars think of her as a buddy rather than a possible conquest.

"It means the guys don't hit on me. Either I scare them off or I put something out that tells them I'm not available and they respect that. They know the boundaries. I'll be their friend, but that's where it ends."

For the past six years, Margulies has been in a relationship with actor Ron (Men Behaving Badly) Eldard. They were living together in New York when Eldard moved to L.A.to work.

On one of her trips to visit Eldard, Margulies was cast in the pilot of ER. Her character committed suicide, but the audience responded so positively to Carol Hathaway that her desperation became an attempted suicide and Margulies has been a series regular ever since.

As serious as her relationship with Eldard may be, Margulies, 30, insists marriage and children are not in the couple's immediate future.

"I'm too young too think about marriage and I'm too selfish with my time right now to consider getting pregnant. I am literally married to ER."

Margulies was the youngest of three daughters born to a dance teacher and advertising executive.

"I was one year old when my parents split, but my mom followed my dad around the world, so we'd have two parents. He always lived in a different house, but he was an influence in our lives."

Margulies' sisters were both excellent classical dancers like their mother, but Julianna preferred riding horses to studying ballet.

"My mother was horrified. She said I walked like a truck driver, so she made me take jazz.

"I'm still very close to my mom. We're in our fourth year of ER, but she still calls me after she watches an episode. She's my biggest fan."

Though she admits ER has a gruelling schedule, Margulies jumped at the chance to spend her summer under the hot Texas sky filming The Newton Boys.

"I'm in hospital scrubs all year long, so it was a joy wearing the 1920 period costumes in The Newton Boys -- even if it was a bit like being in a sauna.

"With my big, broad 1940s face and kinky hair, I've always felt I was born in the wrong era. I felt so at home last summer."

It wasn't just the costumes. It helped that her co-stars proved to be "real Texan gentlemen. The guys were just so sweet. I felt like I had five big brothers."

Margulies is the envy of millions of women. Each week she kisses Clooney on the set of ER and in The Newton Boys, she has some hot and heavy necking scenes with McConaughey.

"They're both great kissers and great guys.

"Matthew is so Texan. He's an open, welcoming, sweet, guy's-guy. George is more of a city boy, which means he's a little more guarded, a little less spontaneous."

The Newton Boys opens Friday and next month she has a supporting role in the drama A Price Above Rubies.