Angelina Jolie appeared at the double-wide doorway of a penthouse suite at the Beverly Hilton Hotel unsmiling and peering warily from behind a curtain of dark hair. Attired in an opalescent, knee-skimming silk dress, she seemed grave -- imperious and businesslike. The actress was flanked by her manager, publicist and two security guards; together the pack had come from an adjoining suite where Jolie's team of hairstylists and makeup artists had just finished plying their trade.

She was here to talk about her critically acclaimed performance in "Changeling," which reached theaters last month and has placed Jolie within a hive of Oscar buzz. She was also here to present an award at the Hollywood Film Festival Awards Gala. Unbeknown to a panoply of Hollywood bigwigs packed into the hotel's ballroom, Jolie had flown in under the celebrity radar to hand "Changeling" director Clint Eastwood a director of the year statuette. (It would be reported later that the crowd "gasped audibly" when Jolie was introduced.)

However, less than an hour before she was to take the stage with Eastwood, Jolie claimed to be in the dark about the night's agenda. Whom had she come to honor? "I can't say. I never know how these things work. I don't even know what I'm doing."

You could excuse the Oscar-winning actress for being a bit unfocused. She had gotten back into the country only three days earlier from a fact-finding mission to Afghanistan, where Jolie met with poverty-stricken families as a U.N. goodwill ambassador. The lack of sustainable infrastructure in that war-torn country and the need to repatriate some 3 million refugees was still very much front of mind.

And such Hollywood concerns, she explained, pale in contrast to the issues that really matter. Like the world beyond the Thirty Mile Zone. And family. Hers includes a veritable Brady Bunch of adopted and biological children she shares with domestic partner Brad Pitt.

"I woke up at 3 in the morning with four kids with jet lag and two babies," said Jolie, 33. "I put myself together for a few hours and go out. And then I go home. This is my job."

She didn't want to sound ungrateful about Hollywood. "I don't dislike it here," Jolie continued. "I just really do love to travel. I love other cultures. And I love raising my kids in the world. I'm so fortunate that I get to do that."

For evidence of just how seriously Jolie takes her maternal identity, look no further than the cover of last month's W magazine, which features a grainy black-and-white photo (shot by Pitt) of the actress breast-feeding one of her twins -- it's either Knox or Vivienne -- in a French chateau last summer.

Considered in conjunction with a succession of paparazzi photos showing her and Pitt with various children in tow (or, alternately, the $14 million People magazine reportedly paid Jolie and Pitt for the first serial rights of photos of the twins in August) you get the idea that it is as a mother -- and not a movie star -- Jolie prefers to be recognized.

"The center of my life is my kids," Jolie said.

Then there is her role in "Changeling," a thriller set in the late '20s that's based on real events. Jolie plays Christine Collins, a Los Angeles woman whose son goes missing but is later found by police. Except, the person returned to her is not her boy. After she confronts authorities, the Los Angeles Police Department not only rejects Collins's story but throws her into the "psych ward" of a county hospital. She must somehow find the wherewithal to stand up for herself -- for her missing son -- and take on the system.

"Christine fought so hard under such incredible circumstance for the rights of other women," Jolie said. "It was a real story that I thought sent a positive message about what you can accomplish. About democracy in action."

In a minutely calibrated performance she based on her late mother, the actress used floods of tears to convey a palate of emotions: despair, rage, indignation, disbelief. Jolie attributed the sharpness of her portrayal in part to Eastwood's run-and-gun style; one that seldom required more than two takes per shot. "You feel you can absolutely break yourself," she said. "You can drain every bit of energy you've got. He's not going to waste your time."

(And at the awards gala, Eastwood returned the praise: "Working with Angelina Jolie is a great privilege because you get to look on that gorgeous beauty every day," he said. "And she's a great talent.")

Viewed in a certain light, "Changeling" arrives as Jolie's fourth-consecutive mom-centric film. She was Grendel's mother in last year's "Beowulf," the heavily pregnant wife of a kidnapped journalist in the indie drama "A Mighty Heart" and in August's shoot-'em-up thriller "Wanted," Jolie metaphorically mothers James McEvoy's transformation from nebbish office worker to killing machine.

Nonetheless, Jolie waves away the notion that her maternal instinct has helped shape any career agenda. "I don't think it's a choice of mine as much as it is something women deal with when we get older," she said. "A woman in her 30s is more likely to have roles that in some way relate to family."

Or vice versa. In this case, she took a role that directly resulted in enlarging her family. Jolie confides that "Changeling's" themes of motherhood interrupted helped push her and Pitt's procreative process. "I got pregnant right in the middle of it and I think partially because of it," she said, smiling at the memory. "I was so emotional about children that I think something in me kicked into gear."