Jennifer Connelly: 'I'm really not gloomy'

She wants to shed her sombre image, she tells Lesley O'Toole. But her latest film has a very serious subject

Four years ago Jennifer Connelly, a smart native New Yorker, won the Best Supporting Actress Academy Award for A Beautiful Mind in which she played the measured, steely Alicia Nash, the wife of the troubled mathematical genius John. Connelly also won a Bafta for the role. But it was not the sort of deep, dark role for which she has so often been acclaimed - in the likes of Requiem for a Dream, Waking the Dead and House of Sand and Fog - and which she evidently relishes.

Connelly's appearance today in unseasonably sunny Los Angeles could not be darker. She is wearing a black, swingy, mini-dress, her long black legs in high-heeled black shoes. Her long hair is as shiny as her shoes, and almost as black, and she is sitting with her legs tucked under her, her arms crossed rigidly.

"I'm really not gloomy. I'd actually love to do a comedy," she laughs. But her new film, Blood Diamond is, in the Connelly tradition, no laughing matter. It is a Sierra-Leone-set depiction of a ruthless trade in African diamonds which funds civil wars on the continent and utilises scores of heavy-weapon-toting child soldiers.

"I didn't know what conflict diamonds were," says Connelly, 36, sounding as if a woman bright enough to have attended Yale really should have known. "It's impossible for me to look at diamonds the same way as before."

But she did not need to interrogate her husband, the British actor Paul Bettany (whom she married on New Year's Day, 2003), about the heritage of her own diamond engagement ring. "We just have these very simple gold bands," she says. "But these earrings are Bulgari diamonds. They came with a certificate. The more people insist on that, the more the diamond industry will have to work to close these loopholes."

Connelly is a mother (of Kai, nine, from a previous relationship and of Stellan, three) and is worried about the world that her children will inherit. "I know my elder son is very concerned about global warming, about energy, about oil running out. In Mozambique I took him around schools and he understood why the children had no books, no paper, no light bulbs. He was so shocked and outraged by it that he wrote a paper for his school. It feels to me a good idea to foster a new generation of Americans who will hopefully be more sensitive to the issues and needs of people around the world."

To these ends, Connelly says she recycles furiously and drives a hybrid car. She has also been working for Amnesty International, as part of its Artists for Amnesty group, for several years. "Africa made me feel like I really don't do enough. We tried to do what we could when we were there. I think just making the film there was a great thing. We all felt good about putting 40 or 50 million dollars into the economy. We created this fund which was then matched by the studio [Warner Brothers] to help the very local communities in which we worked. I called Amnesty when I got home and asked them to put me to work whenever they can. But you do leave there thinking, 'Gosh, I wish there was more I could do'. And I'm sure there is."

She is not precisely sure what. As anyone who has been to Africa knows, and as Connelly's war reporter Maddy Bowen demonstrates, there is no escaping a nagging feeling of helplessness. Connelly is already grieving in a way, for the children she befriended in her free time spent at a local orphanage.

"Leaving them was just devastating. I've tried to stay in touch. You start to forge friendships over time and then you leave, and I really had to ask myself some questions: Was it worse to have gone and created relationships and been another person who left? Or would it have been wrong to have done nothing at all? Not to have even given them that amount of love? And I can't feel like I'm off the hook because of the things I've done. Compared with what needs to be done, it's nothing."

I ask Connelly if the experience prompted her to think about adopting a child. "We absolutely considered adopting. We have a son who went through a separation of his parents [Connelly was previously involved with the photographer David Dugan] and then a new stepfather and a new sibling. He's had a lot of change so of course I really have to be sensitive to him. One of the kids I became close to was older than him. What would that mean to my family? Would my son feel displaced, all of a sudden having an older sibling who didn't speak the language and would need so much more time and attention? These are all concerns of mine and reasons why I didn't come home with a child even though, believe me, I would call Paul at night when he was away. I'd say [imitating a teary voice], 'There's this baby and I don't know what to do and I love him so much and if I leave here he might die'." She sighs deeply, her intense green eyes looking glassy. "It's complicated, but we are still considering."

This is not the Jennifer Connelly who used to come with a warning, the one who admits she was guilty of taking herself a mite seriously. "I remember Paul would sit in my trailer on House of Sand and Fog strumming his guitar and singing, 'Oooh, my name's Jennifer and I'm a very serious actress and take myself seriously', and that sort of thing.

"I think I can honestly say now that I never fitted in until after I had kids. I had no balance when I was in college because I was trying to figure out what was mine and where I wanted to be and where I felt safe. Suddenly the answer was the love I felt for my son."

Growing up fast is almost certainly key to the sort of young woman Connelly became. When she was 10, she began auditioning for commercials and modelling jobs. The 11-year-old Connelly played Elizabeth McGovern's character as a young girl in Serge Leone's 1984 gangster epic, Once Upon a Time in America. It was the start of a career in film which saw Connelly working constantly, with no perceptible phase as she crossed the child-woman divide. She abandoned academia (she had left Yale and enrolled at Stanford).

Now she is ready for a break. "I'm going to pack my bags, go to the airport, get my kids and then tomorrow we're all going to Italy to see Paul."

'Blood Diamond' opens on January 26.