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

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 started to really enjoy the fact that [princess] Margaret was an exhibitionist. Even on a day-to-day basis, Margaret's costumes were always so much more dramatic and bold than Elizabeth's were.

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

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.

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.

That's exactly how I felt. So getting to suddenly know this young [princess] Margaret, who had this extraordinary life - it was sad and tragic and difficult and sort of astonishing and getting to know her young self was amazing because it completely defied all my expectations.