There are movies where I've walked onto the set and felt, "This is home," and I'm confident in myself and my work, but that was my first experience of live TV. At that stage, Friends was at its unassailable height of popularity and brilliance.

I have many debates now with friends on the changes, and the continuing confusion over bringing up your children, instilling values, letting them make the right choices.

There's this absurd situation on a movie set where your trailer's here and the set is here and the lunch tent is here, and you're not allowed to get yourself from these three places.

I hope I never get in the situation where I refuse to audition, because I think people have a right to see you interpreting the character, and if you don't do it the way they want you to, they have a right to say, "No."

Joss Whedon writes beautiful drama. His sensitivity and his sense of drama and scenes are pretty exceptional. There's no one else writing like him, really, in sci-fi and TV. That's not to say there are no astonishing writers on TV. I was nervous about coming to America and playing an English person who speaks very English when all the writers are American, because it's a very particular thing to imitate, and if it's badly imitated, it sounds painfully contorted and silly. And he writes very well for English people. It was Joss Whedon who persuaded me.

Working with Roman Polanski is funny. It's like anything in life - someone warns you that something's going to be amazing or difficult or awful, and you say, "I can do that. I can cope with that." And then when you're in the middle of it, it may be joyful or tricky, but it's never difficult in the way you think it's going to be difficult.

I really needed to have something in my life, because I realized there were other things more important than my career. So I love having my children and my family.