I did a lot before [being cast] because I knew how important it would be for playing somebody real, or attempting to - to show the team [the role] was something I would be fascinated to do. I read a couple of biographies and I watched everything I could find [about princess Margaret].

[Queen Elizabeth] is just the granny queen! She's our granny queen who shakes people's hands!

Everybody has an image of [princess Margaret], to a certain extent. But I felt it would have been harder if we were playing them as they are now. In a way, I don't know how much of a living memory we as a collective have of them in the '50s, when Margaret was 21 and this sort of Elizabeth Taylor. You don't think of your grandparents as being teenagers. You just can't - your brain just can't go there!

I really enjoyed stepping into that side of [princess Margaret] and being silly and naughty and fun.

At the same time, [princess Margaret] had a fragility and an insecurity in who she was and her position, because her sister had always got the education ever since David [Edward VIII] abdicated.

I would argue [princess] Margaret is the tragic figure of the century.

Marking the differences between them was really important. It just became second nature. When we were choosing pajamas or something, instantly you'd be able to spot: those are [princess] Margaret, those are [princess] Elizabeth. It became this sort of language, really, of the two sisters.