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.

[Princess Margaret] was loud, an extrovert, an exhibitionist, loved fashion, loved color, loved music, loved drama, loved the theater, wanted to be a ballerina or actress, was always the little one putting on the school plays, and [princess] Elizabeth reluctantly did it and got stage fright.

I remember somebody saying something to me about Frost/Nixon, when Anthony Hopkins does his famous speech, and the difference in the way Anthony did it was to dramatize, essentially, what was a documentary-style version of that speech. I remember someone saying to me, "There is artistic liberty."

[Princess Margaret] was always trying to radicalize things.

I watched her do speeches, but the only footage we could find of [princess] Margaret was archive footage, which was of her public presentation of herself.

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].

I watched tons of archive footage of princess Margaret and listened to the music she loved; that was really immersive and brilliant.