FOR MOST ACTRESSES, movie stardom is the ultimate achievement. After all, it's a tough business, and only those with a strong desire to succeed can reach the summit. But that's not the case with Taking Lives star Angelina Jolie. The 28-year-old says that, if she had to choose between appearing in movies and her job as a United Nations goodwill ambassador, she'd choose the latter. Jolie's work for the UN has taken her to war zones and refugee camps around the globe. 'I became more aware of the world when I started to travel,' she says. 'And that's given me a social conscience. I think travel has that effect on most people. These days, I don't live in Hollywood, and I try to focus on things out there in the world, rather than just myself all the time. If I was just an actress, I wouldn't feel that I was contributing much to anything. It would be a very shallow life and, at the end of the day, I don't think I would feel very good about it.' Jolie's character in Taking Lives has a similar wish to make the world a better place. But it doesn't entail campaigning for peace - she does it by catching serial killers. Jolie, who won an Oscar in 2000 for her portrayal of a mentally ill woman in Girl, Interrupted, plays FBI profiler Illeana Scott, a woman who spends her life scrabbling around in graves looking for clues. Scott is sent to help detectives searching for a killer in Montreal, a French-speaking city on Canada's east coast. Once there, she falls out with her new partner, Paquette (French heart-throb Olivier Martinez), who resents having to work with a Yank on Canadian soil. To compensate, she has a fling with a friendly artist, played by Ethan Hawke. Things get complicated when the cops ask Hawke to act as bait for the killer - something that puts Scott's romantic liaison in jeopardy. It's a gory and somewhat cliched film, which nonetheless delivers a few short sharp shocks. Jolie plays a sensitive but strong cop who's trying to do an unpleasant job the best way she can. 'This woman is smart,' Jolie says. 'Much smarter than me. That's why I wanted to do the film. It's much more than just a thriller, as it has a lot of extra levels to it. It's a great study of human behaviour. The relationships that occur inside the closed world the writer has created are really fascinating.' Scott has a feminine strength that's characteristic of today's career women, says Jolie. 'I think she's like me when I'm working, or having a meeting, or fighting for something,' she says. 'In those situations I'm tough, so I probably appear what people consider to be masculine. But I don't see strength as being only a masculine quality. Women have a lot of strength, too. What I see in this movie is a woman who is clear and strong about what she wants, not one who is emulating a man.' Jolie has to play some emotionally disturbing - and physically frightening - scenes in the film. 'To shoot a scene where you're being abused in any way is always very difficult,' she says. 'It makes you feel really bad emotionally. It's also bad for the actor who's doing the attacking. It's no fun for him, either. So, everyone gets a bit freaked out when you're filming those bits. 'To act those scenes convincingly, I generally try to scare myself by thinking about something that makes me feel vulnerable,' she says. 'I usually think about my son. I imagine myself locked in a room while someone is beating him up. That makes me feel scared and threatened.' Jolie's adopted son, Maddox, is from Cambodia. She now splits her time between Buckinghamshire, in England, and her son's village. 'Cambodia is a lovely place with lovely people,' she says. 'It's my son's country, so I want to be there sometimes. We live in a place in the jungle, in an area which has been cleared of mines. The only way to get there is by helicopter. We live on these three little houses built on stilts. 'I know my neighbours, as I did aid work there,' she says. 'Our house borders some land that's been taken over by a project that's trying to stop deforestation and poaching. We have rangers, and we're working to protect the forest. It's quiet there, and I can live a normal life, without being recognised all the time.' The jungle doesn't scare her. Like Lara Croft, the fearless adventurer she played in Tomb Raider, Jolie doesn't frighten easily. 'I'm not scared of spiders. They eat them there, anyway. I'm not really scared of anything, except something happening to my son,' she says. 'Maddox knows how to look after himself in the jungle - but it's still a jungle, and I have to make sure he doesn't run off into the wrong corner.' Close up, Jolie's features resemble those of her father, Jon Voight, who left the family when she was very young. (Jolie uses her second name, rather than her family name.) Her bad girl image is nowhere in evidence. She's polite and chatty. She likes to drop hints that she's a bit unconventional, but it seems she wants to be portrayed as a good mother rather than a Hollywood rebel. That didn't stop her revealing secrets about her sex life recently in the tabloid New York Post. But the actress, who has been married to British actor Jonny Lee Miller and Billy Bob Thornton, says she isn't having much luck getting a man. Is that because they think she's too scary? 'I don't think men are scared of me, but then I don't seem to have one at the moment,' she says, laughing. 'I haven't found a great partner, and I've been married twice. But I don't think it's because they're frightened of me. I think I probably have other problems which put them off.' But she doesn't really care, she says. 'I wouldn't turn down the perfect man, but being a mother comes first these days.' Taking Lives opens today.