My whole family is quite petite, so I have good genes on my side. But I find it quite tiresome that we have to keep talking about sizes and how much weight we can lose.

You can see when an actor gets bored: Their eyes go dead. I promised myself I'd never let that happen. If it does, I'll go and live on a desert island for a year.

People became more interested in my love life than in me, and that has a certain effect. You start to feel very empty and worth nothing, you start to become a piece in a board game you never wanted to play.

There were reports of me using fat-sucking machines and all sorts of silliness. All I did was walk a lot and breast-feed. I've never been on a strict diet. I just don't overeat, and I don't eat if I'm not hungry.

Any scene that involves stripping off is hell. You just know it's going to take a day or more to get it right. It never gets any better and it's always uncomfortable, and all you can do is grin and bare it. I just pray it's never gratuitous and that it doesn't look so fake that all you hear in the audience is, 'Well, that's not really her, is it?'

I'd like to put the record straight about that. I've been labelled an irresponsible role model for young mothers, but none of it is true. I couldn't even walk for two weeks after the birth, let alone exercise. I ate very healthily all the way through my pregnancy and afterwards. I didn't do anything extreme.

The doctors say it dates back to a film where I had these huge prosthetic breasts because my character was breast-feeding. The weight of them, and of the baby, did my back in.