What research did you undertake to play Iris Murdoch in "Iris"?

I dipped into some of her novels, just to get a feeling for them. I wanted to get a sense of what she was like as a novelist, what it was that motivated her. It confirmed things about her that I already felt and knew from John Bayley's books - that she loved people and had an incredible zest for life.

Was the prospect of doing nude swimming scenes a problem for you, especially after having Mia?

I suppose these things are a big issue for some people, but when I was pregnant I didn't panic desperately and go "oh I've lost my figure forever". When you're pregnant your body changes and you gain weight. I gained a lot of weight. With some people it just drops off, but with me it didn't, so there was a lot of hard work to get back to where I was before. But I do now weigh the same as I did before having Mia.

Has your approach to work changed since becoming a mum?

I've never chosen to work back to back so it hasn't really changed, though I think I anticipated that it might.

How did it feel to get such a positive response for your performance from John Bayley, Iris's husband?

That was better than any review, any award, or any nomination. It was fantastic. I was delighted to feel that at least I'd made him happy in some way.