Charlize: I'd kill if I had to

Apparently, there was a family party that got out of hand. Charlize was accused by her father of snubbing his relations by not saying hello to them. Charlize and her mother left the party, went home and locked themselves in.

When Charles Theron came home, he blasted the gates and then the front door open with a shotgun, apparently saying he was going to kill both Gerda and her daughter. After a lot of commotion, Gerda shot her husband dead. She was acquitted of the crime by the South African attorney-general on the grounds that she was acting in self-defence.

The one thing Charlize Theron always says is: "If my daughter's life was threatened like that, I have no doubt I would act in exactly the same way." What she says today is: "I really don't want to talk about this. So many other events have happened - like winning the Oscar for Monster and the amount of time and energy I put into the role.

"And I produced the film. I didn't take a fee for it and I ended up putting my own money into it. I paid for the posters. If you could only understand how hard it was to get anyone interested in it ... They were all, like, 'Charlize Theron? As Aileen Wuornos? Oh, come on.'"

BUT it's not that far-fetched that she should understand what could drive a woman to kill. Wuornos started her killing spree in the late 1980s. She was from a very underprivileged home, allegedly abused from the age of eight by a friend of her father, who did nothing to protect her. By the age of 13 she was a prostitute and pregnant. After being abused by one of her clients, she shot him dead. Over the next year she shot six more men until she was finally caught and convicted of first-degree murder in 1990, spent 12 years on death row and was executed by lethal injection two years ago.

"Yes, it was pretty harrowing," says Theron about the role. She doesn't want to go into whether her mother's experience - shooting dead an abusive man - was something she drew on for her performance; she just says she is very proud of her achievement in doing the film and winning the Oscar. "Look, I struggled to get here. I really did. I paid my dues. For five years, five long years, I worked as a model. I moved away from home when I was 16 because I was offered a modelling contract in Milan and my mother said, 'Charlize, make a life for yourself outside this country', and it was such a great opportunity. But there I was, a young girl, trying to hold my own in a country with no friends and no mother. And I hated modelling."

To keep herself sane, she took ballet classes and later toured with the Joffrey Ballet Company. "We were based in New York," she says. "I lived in a shithole. I was not at all happy." She went to LA "on a whim" and was spotted having a monumental tantrum in a bank - "The teller wouldn't cash my cheque!" - by legendary Hollywood talent scout John Crosby.

"He gave me his card and said, 'Call me,' and I thought it was all a bit of a joke." The rest is history - she went on, pretty quickly, to star in Woody Allen's Celebrity, The Legend of Bagger Vance, The Devil's Advocate and The Cider House Rules as well as last year's remake of The Italian Job.

She lives and breathes the parts she plays, she says, and fails to understand why more actresses don't take on challenging roles. "I hear well-known actresses every day saying, 'Oh, I don't want to do that part because it just doesn't sound like me,' and I think, 'Well, what the hell do you think acting is about then?' It's supposed to be challenging. It's supposed to change the way people perceive you. I'd rather have no character because then I can take on any part."

She was confounded when people asked her how she felt about her body when she'd put on weight to play Wuornos. "I didn't think about it," she says. "I put it on quickly as we had to shoot within days of deciding to go ahead with the movie. I told the crew I had three pairs of jogging pants and that's all I was going to wear. My body changed to that of a dispossessed woman's. She drank a lot. She smoked a lot. She'd never been to a gym. Can you imagine what that does to your body?" Unfortunately, I say, I can. Theron looks puzzled.

But fame, at the age of 28, has brought her the usual things plus a beautiful boyfriend, Irish actor Stuart Townsend. They met when they were making a movie together called Trapped. Was it love at first sight? "It was pretty instantaneous, and we're very happy together," she says.

"He's very supportive. At the Oscars, when I thought I was going to break down in tears and I had promised myself not to, it was him who kept me together. My mum was desperately trying not to cry but I could see the tears welling up in her eyes and that was when I thought, 'Oh God, I'm going to lose it.' "

The couple share a house just off the beach in Malibu. And they have beautiful friends - Keanu Reeves, Tobey Maguire, just about anyone she's ever worked with.

Theron has access to important people, so much so that names just slip into the conversation. "I was talking to Nelson Mandela the other day," she says, "and we were discussing poverty in South Africa and how that affects the crime rate. The biggest problem is Aids and rape. Some men there believe that the only cure for HIV is to sleep with a virgin. A woman gets raped every 26 seconds."

Eight years ago, she starred in a hardhitting anti-rape campaign. "Yeah," she says, "Twenty eight men complained and the government tried to ban it because they thought it would put tourists off, but we got the ruling overturned."

Despite her American accent, and even though her mother lives near her in Los Angeles, she still misses South Africa. "Of course my mother and I miss home but we are happy to be together. We have an incredibly strong bond," she says.

"If you think what she's done for me ... After my father died she took on the construction company. It was a hard job and she was having to be a woman in a man's world, but she persevered and made a success of it. She taught me so much about strength and honesty. I feel very emotional when I talk about her."

But fame has also brought its downside. After the Oscars, Theron went back home to celebrate. "There were loads of people at the airport all cheering me and stopping me wherever I went. I was very touched by the attention and the joy."

But there was another set of people, namely her father's relations, who were not so joyous. Her paternal grandmother complained that Theron had not spoken to her since the death of her father and various other aunts appeared to say she'd grown too big for her boots.

"All this stuff is so inevitable," says Theron. "I just try to get on with my life and not get involved in other people's. I am really, truly happy and I don't want anyone to rain on my parade."

With that she sits up and gives me a dazzling sunbeam of a smile. Then she says, almost as an afterthought: "Ooh, I just want to make one other thing clear." Yes, I say. "Because my story does seem like a fairy tale, some journalists have been reporting that I must have slept my way to the top. I can say now that I categorically did not. The thought never even occurred to me."

What, never? "No," she says, "but I wish it had. It would've made life a damn sight easier!"

Monster opens nationwide today.