Possessor of one of the loveliest faces on the planet, Charlize Theron (search) still finds herself explaining to people that sometimes it's part of her job to hide her looks.

The attention critics and audiences paid to her physical transformation in 2003's "Monster" grew tiresome for Theron, who had gained 30 pounds and became almost unrecognizable behind splotchy makeup and dark contact lenses to play serial killer Aileen Wuornos.

Theron faced endless questions about how and why she concealed her cover-girl beauty.

"The celebrity status in Hollywood has gotten really out of control," Theron told The Associated Press at September's Toronto International Film Festival (search), where her new film "North Country (search)" premiered.

"Like one of those snow-globe things, it's this fragile little ball of perfection, and I think people have forgotten what actors do. After a while, I was like, `Well, what did you want me to do? Did you want me to play this woman and not look like her?'"

That focus on her appearance gradually subsided in a wave of newfound respect for her as a serious performer, culminating in her best-actress win at the Academy Awards for "Monster."

The posters for the blue-collar drama "North Country" resurrect the beauty issue. It's a tight shot of Theron's face, looking not homely, but drab and gritty, her face ashen, her blond hair wrapped in a yellow bandanna.

Based on a true story, the film stars Theron as a single mom doing hard labor at a Minnesota mining operation; she leads a sexual-harassment lawsuit against male co-workers angry that women are taking on jobs traditionally held by men.

"People said, 'Oh, you're doing another ugly movie,'" Theron said. "I said, 'No, I'm doing another film about real people, and it's not about ugly vs. anything.' It's about searching for that constant truth, and I don't think I'll be able to sleep at night if I know I didn't search for that truth and implement it. I don't know how else to do it as an actor."

Theron undergoes another transformation late this year, playing the black-haired, sleekly clad action anti-hero of "Aeon Flux," based on the animated sci-fi series.

A former ballerina and model, Theron, 30, has dealt with the pretty-face syndrome since she decided to try acting in her late teens. At first she did not even tell friends she was taking acting classes, "because I knew the whole model-turned-actress thing, it's not something where you go, 'Well, that's something to look up to.' I think there's just an initial reaction toward it that's very negative," Theron said.

From her first film role in "2 Days in the Valley" through such movies as "The Devil's Advocate," "The Italian Job" and her Woody Allen collaborations "Celebrity" and "The Curse of the Jade Scorpion," Theron had proved herself a competent actress, but her looks always overshadowed her dramatic chops.

Her best performance came in "The Cider House Rules," yet many of her movies had been critical and commercial duds such as "Reindeer Games," "The Legend of Bagger Vance," "Sweet November" and "Waking Up in Reno."

Lightweight films can result in a lightweight reputation, and Theron found herself generally relegated to roles as the beautiful girlfriend. Serving as a producer on "Monster," she finally was able to break out of that mold.

"You've got to be pretty to get their attention, but then that becomes your prison, as well," said "North Country" director Niki Caro. "She was never given an opportunity until she took the opportunity herself with 'Monster' to show people just how much depth and how much character she's got.

"Her physical transformation was really interesting and astounding, but it was her emotional transformation, what she was doing emotionally in that film. Her work was unbelievable."

"North Country" co-star Woody Harrelson, who plays Theron's romantic interest and the lawyer handling the lawsuit, said the actress went to great lengths to get into her character's head.

"Me, I'll cut up and horse around right up until they say 'Action!'" Harrelson said. "But I loved seeing the preparation, the time she took. Before the cameras roll, in between setups, she is so present in the depth, in the feeling of what's going on with her character. And then, of course, you see the movie, and it's an amazing performance."

A native of South Africa, Theron grew up on a farm speaking Afrikaans, learning English only after she came to the United States as a teenage model.

She credits her tough rural upbringing, where survival meant focusing on the task at hand, for helping her cope with tragedy in her life. When Theron was 15, her mother shot and killed her father in self-defense during an argument. In the late 1990s, Theron's stepbrother died in a car accident.

"I think we all have a well we draw from, and there is a healthy way to approach it and a non-healthy way," Theron said. "I feel extremely healthy. I don't feel damaged. I'm not haunted. I come from a community where you just don't do that. There's no choice. You move on."

With "Aeon Flux," Theron plays an assassin dispatched to kill a leader of a despotic government 400 years in the future, after most of humanity has been wiped out by pollution.

Not typically a fan of action movies, Theron was drawn to the project partly for the physical challenges, which were reminiscent of her ballet days. She was mainly eager to work with director Karyn Kusama, whose independent drama "Girlfight" she greatly admired.

"I sat down with Karyn and said, `You don't understand. I don't know these kind of movies,'" Theron said. "I grew up on 'Kramer vs. Kramer' and 'Sophie's Choice.' I never saw 'Star Wars' or anything like that, and the funny thing is, when I get dragged to go and see these films, I love them.

"But my natural inkling isn't really to go do those kinds of films, so I really wanted to go experience that and see what is interesting in that genre and what to do with it and come up with a female hero that wasn't the perfect heroine. She was very flawed and very dark. I liked that a lot about her."

Going from Oscar winner to action hero may turn as many heads as going from pretty face to overweight serial killer. But since she broke the bombshell barrier with "Monster," Theron wants to continue broadening her Hollywood repertoire.

"I was never just interested in playing that one note," Theron said. "I wanted to go and experience things that initially, I think, when people looked at me, they didn't think I was capable of doing.

"And also it's a little bit of, the more they say, 'No, you can't,' the more you say, 'No, you know what? Yes, I can.'"