Why Kidman was brave to speak out

Last week Nicole Kidman told the US Congress that Hollywood contributed to violence against women by portraying them as sex objects, and Matt Damon revealed that he turned down scripts if they featured gratuitous violence. How hard is it for actors to make decisions of conscience?

I have a huge issue with Hollywood actors who don't use their power in a way that's really constructive. For example, if they do a big blockbuster action film and they're playing someone violent, yet they don't have a say over the movie's poster and whether they appear naked in it, or with weapons. What does that say to the children who are in the backs of cars being driven around cities?

I do have a say in those things and if people don't want to work with me, then they don't. You want to be proud of all the choices you make and your reasons for making them.

When I receive a script the first thing I ask my agent is: what's it about, who is making it and who is producing it? These considerations are not always straightforward. When, for instance, I was sent the script for Longford (2006), in which I played the part of Myra Hindley, my initial instinct was: no. "It's a very good script," my agent said. "I don't care," I replied.

But I trust my agent, and when I read the script, I felt educated by it. So although that role attracted public dismay as well as critical acclaim, I felt my performance was part of a bigger message.

But not everyone gets it. After I played Iris in Under the Skin (1997), a woman who was harming herself through sex and being very promiscuous as part of a medical condition, I got sent every script going for women who would open their legs at anything. I was reading them thinking: "There's no reason whatsoever for making this film."

Actors can be manipulated. You can think you are involved in something with a message, and it can turn into something else altogether. You are at the mercy of the director, the director is at the mercy of the producer, and the producer is at the mercy of the financier. People can change the script while you're working and they have the right to do so. And you have to cooperate, otherwise you are deemed unsupportive.

A scene can be directed in a way that you had no concept of. A film I made recently, which I thought was about one thing, somehow turned into a different kind of film altogether. I had no idea that was going to happen. I felt abused by it.

I admire Nicole Kidman for speaking out. It was a brave thing to do. For her, the difficulties multiply – it's a different world. You have obligations, you have to respect the studios that keep employing you. You probably have houses all over the world you would like to keep . . . It must be hard at times to keep making conscientious choices – and not everyone does. Some people think they just want to act, and don't care about the broader message.