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

I knew she was a party girl. The book I liked most on her was called [princess] Margaret: A Life of Contrasts and getting to know her, it was how conflicted her position and her internal life - or self - was. She is so fiercely royal and so fiercely "sister of the queen" or "daughter of the king" because that is her identity and it's all she's ever known. And at the same time she is struggling to push the boundaries and to break away from it, to be different or to modernize the monarchy, to turn it on its head.

People are so much more fascinated by the royal family generally than in England.

My dad is a big extrovert - he's a doctor - but he always loved [William] Shakespeare and he took us to tons of theater.

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.

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

I still get stage fright horribly. I still get nervous. I do tend to find when you're playing characters, often - just for the time you're playing them - there are sides of your personality that get stronger because you draw on them more.