In The Bourne Legacy, Rachel Weisz plays geneticist Dr Marta Shearing - who is forced to team up with Aaron Cross (Jeremy Renner) in order for them both to survive a targeted "clean-up" operation.

How do you explain the popularity of the trilogy?

I think the Bourne trilogy was very popular because it has a very realistic feeling to it. It's an action drama, but it's not a super-hero film.  It feels real. When the stunts are happening, it feels very realistic and smart. I think there's room in this world for smart thrillers.

It's a sequel, but it's not really a sequel. Everything's changed, and everything stays the same. Was there any hesitation on your part to go for that?

There was no hesitation. Tony Gilroy wrote and directed this. He wrote the first three Bourne films, so he's really the architect of the whole Bourne universe and the mythology.  I feel like he knows more about the Bourne world than anyone else on the planet, so I was thrilled to come on board and work with him. I was also a huge fan of Michael Clayton, the film he wrote and directed, so I really wanted to work with Tony.

There's something in Michael Clayton that I really like. It's the coldness of the directing, the mise-en-scene. The first murder scene with the lawyer is an example. It's kind of the same with some sequences in this film. How does that translate on set? How does this coldness, this very surgical type of directing that he has in the action scenes, translate on set?

That's interesting.  I've never really thought of it as coldness. Yes, I suppose you're right.

It's kind of like the killing in this movie, correct? In the lab, it's kind of the same thing.

I wouldn't call it coldness. I'd call it hyper-realism. I'd say it was un-sensationalised, un-glamorised, and incredibly real. For me, that's not cold. It feels more like reportage, like it's actually happening. Reality is never cold.  Reality is the warmest, fullest, richest way possible to tell a story. I think we've seen so many films where things get so exaggerated and over the top that maybe it feels cold, but I think it's hot and warm and real.

How does he do that?

That's his taste. That's his eye. The tone of a movie comes from the director.  Sometimes a movie director can't even sustain a tone that's all over the place, but Tony maintains a tone of realism. I don't know how he gets it. That's what the director's job is.  It's a mystery to me. It's his instinct.

You're talking about realism, but how do you keep your work very realistic in something that is over the top? It's action, action, action. How do you keep the realism when acting?

The stakes are very high. It's a very extreme story which is what drama can often be about, but that's my job. My job is to try to make it real, moment by moment, page by page, and scene by scene.

What I like about the movie is that it's a big spy action movie. However, if you strip away everything, it could be the story of an addict trying to get his fix. Did you see that? Did you like that?

Yes! I think it's very human and relatable.

What's your character's role in the story? How did she fit in the Bourne saga?

Both Jeremy Renner's character and my character are completely new characters. The curtain gets lifted on the first three Bourne films. You find out who was really in charge.  If you think you knew who was in charge in the first three, you were wrong. You didn't know. You get to see who the puppet master is. I play a scientist who's working on a government research project in which Jeremy Renner's character is involved. He's sort of my guinea pig, but we get thrown together. I can't stay alive without him, and he can't stay alive without me. It turns out that we both have a very strong desire to live. I go from being a scientist to a warrior because I want to live so much. I don't want to die.

Jeremy's a great actor, but I wondered if he was right for Bourne. After I saw one shot of the movie, my doubt was gone.  Was it the same on set?

Yes, he's a tremendous leading man. He's got danger. He's got gravitas. He's got edge. He's got empathy. He's got vulnerability. He's playing with a full deck of cards. I think he's extraordinarily talented and a huge star.

How did you two work together in scenes that had more dialogue than action? Did you work well together?

I loved doing all the more intimate, intense dialogue scenes with him.  We both work in a really similar way, as we don't like to talk about the work.  We just do it.  Tony doesn't ever rehearse, which both Jeremy and myself really like. I loved working with Jeremy.  We had a really good time.

In relation to other action movies, the Bourne series seems to ask a lot more from the actors. It builds characters into the action genre. Is this genre more attractive to you now because of that?

Yes. I can't really think of many other action movies that have such complex characters and such smartness and realism. I'm not an expert on action films, but I was a real fan of the Bourne trilogy because of the characters. I like realism on film, which is why I really like the Bourne films.

When you do a big blockbuster like this, is it really different from doing an independent film?

If I was going to generalise, my heart lies more with independent filmmaking only because I like that it's a struggle to get the movies made. I like to try and fight for a movie to get made, to raise money for it. However, I also like to play an interesting character that appeals to me. Whether the movie costs a lot of money or a small amount of money, it doesn't really affect my character.

The Bourne Legacy has a pretty open ending. Will we see you in future Bourne films?

If there is another one, I would definitely love to be a part of it. I haven't read anything or I don't think anything's been written. I think it could happen though. The future's open, as you said.

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