The American-born star, 43, has a major role as a CIA officer in the thrilling action movie Zero Dark Thirty, which is the hottest tip for a Best Picture Oscar.
She lives in America with writer husband Michael Ryan and children George, nine, and Talulah, three.
She tells GARTH PEARCE what she wishes she’d known at 18.
“I WISH I’d not taken off all my clothes in my first television series, The Camomile Lawn.When I took the job, I did not realise there would be so much nudity. But no one forced me to do it.
I played the young Calypso (her English actress mother, Rosemary Harris, played the character as an older woman) and had some very full-on scenes.
I only got British citizenship the year we did Pride And Prejudice. I thought London would be a nicer city to be unemployed in than New York or Los Angeles.
Colin Firth? He is a very nice guy and a very good actor. We did have a relationship for about a year. But by the time Pride And Prejudice came out, we were not a couple any more.