By Jenny Halper in New York City

Rachel Weisz isn’t one to mince words. So, when a journalist hesitantly comments on her “Constant Gardener” character’s very early death, Weisz responds swiftly:

“She's murdered in the first two minutes of the movie. I think it's OK to say that.”

Weisz may not be an activist like her character, Tessa Quayle, but she seems to share her passion for Kenya and its citizens. When Tessa’s persistent convictions result in her murder, husband Justin (Ralph Fiennes) trots cross-globe to investigate her death.

The actress, who also stars in Darren Aronofsky’s highly anticipated “The Fountain,” recently spoke with press about traveling to Kenya and working with “City of God” director, Fernando Meirelles.

Q. You play a deeply politically committed character in this movie. What political issues concern you in the real world?

RACHEL: That was my challenge playing this role. I've always been fascinated by activists, people who will devote their life to a cause, people who go to India and to Africa and put their life in jeopardy to do what they believe is right. In reality, the main thing that keeps me awake at night is probably the destruction of the planet; that's what gets me pretty upset.

Q. Were you excited by the challenge of being able to improvise, especially working in an alien environment like Kenya?

RACHEL: Very much. The way Fernando works, he really values spontaneity and improvisation. He allows you to stray from the text and try things, play, be very free. I like to work like that and, luckily, so does Ralph. Because some actors don’t. Some actors like to stick to the next. There's nothing wrong with that. They like to do each take pretty much the same and perfect each take as they go. But Ralph and I both like to try new things. If the love story is believable, it's because of that. It has the kind of banter that a couple have that’s very hard to script because couples interrupt each other and life is messy- not neat like a script.

Q. Did Ralph improvise the Jacques Cousteau scene?

RACHEL: Absolutely. It was a wonderful moment. There were so many moments like that in the film where something happened. That’s really due to the way Fernando allowed us that freedom. Directors, on the whole, like to control things. They like to know exactly what's going to happen and how it's going to happen. Fernando has a great humility about him and he allowed us to kind of take over. In those scenes where we were filming in the slum of Kibera, we were just walking around with a tiny camera. . . We led the camera, the camera didn’t lead us . . . and that’s a pretty extraordinary situation.

Q. Do you do a lot of research?

RACHEL: In England, Oxfam was very generous. They allowed me to talk to a lot of people who had been working out in the field. . . All that research was great, but the real inspiration happened in Africa. When I was there, there was a woman who was an activist. She was a Kenyan who had been living with HIV for the last 12 years and she was a counselor for woman with HIV in the slums. She was incredibly generous and allowed me to accompany her on house calls around the shantytown to visit patients with her. Really meeting the people of Africa was the inspiration. I'd never seen poverty on that level ever in my life. It's very extreme: no sanitation, no running water . . . and a very high level of disease. And yet, there was a kind of spiritual wealth that these people had that was so overwhelming.

Q. What was your reaction when you saw the film?

RACHEL: I love the fact that's it’s a retrospective love story, that it's told in flashback and there are a lot of assumptions that Ralph and the audience make about my character which are then revised as the film goes on. I think it’s a beautiful narrative structure that’s very original.

Q. Is this a thriller, a political corporate expose or a love story?

RACHEL: What I love about the film is that I think it's all three things. It is a political thriller. It's very action packed and it's very exciting, but at the same time it’s a very big soulful love story about longing and loss. They're not separate, they're completely dependent on one another. As Ralph's character begins to discover the political thriller aspect of the film, he falls deeper in love with his wife, so the two run together. That's the beauty of this film. It has fast pace and excitement, but it also has heart and soul.

Q. How can a political activist fall in love with a man who's not politically active?

RACHEL: I don’t believe your soul mate has to share your politics. I think he is as moral and as good as she is and has as much integrity as she has. He's a very good man, but he doesn’t go looking for trouble. And she's the kind of person who does. She's a very unusual person. If there's some injustice being done, she will sniff it out. She's the unusual one. He is just a good everyman. He's not aware of this level of corruption that there is. I think the love story is about opposites attract. She is volatile and flighty and likes to rock the boat; he's the exact opposite. He's a diplomat, he likes to keep the peace, he's very emotionally reserved. He's her rock; he gives her stability and she feels immediately safe with him.

Q. Ralph was telling us that given this was shot in Africa, this production could have been a lot more complicated…

RACHEL: Simon Channing Williams, the producer, behaved incredibly responsibly in the filming in Africa. Sometimes, Hollywood crews can go into developing countries and behave less than well. He gave the script to the people of Kibera, so they were aware of the story that we were going to be filming in their midst. We didn’t go in and surprise them. In exchange for using the location, we built a school there, we built a bridge and provided showers and running water. We also set up the Constant Gardener Charitable Trust, which will be ongoing charity. . . We just wanted to say thank you to the people there. . . It was a very beautiful exchange.

Q. What's happening with ``The Fountain''?

RACHEL: “The Fountain'' is a love story with Hugh Jackman and myself. It's set in three time zones: 16th-century Spain, present-day America and distant future space, so it’s a science fiction love story in that sense. ``The Fountain'' refers to the search for the fountain of youth. It's very emotional, it's very raw and it's very beautiful.

“The Constant Gardener” opens on August 31st.