[Princess Margaret] was always trying to radicalize things.

Once you start [filming] you have researchers who are constantly giving you information. Ultimately it isn't about impersonating or trying to be an image of somebody and more trying to capture the spirit and the soul of the person somehow.

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

[Princess Margaret] was always trying to radicalize things.

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.

It's this amazing combination to play, really, of somebody who's actually very fragile and hasn't really grown up properly yet - at least in a healthy environment - and has suffered immense loss with her dad - like that line where she says, [in the words of her father [King George VI], "Yes, 'Elizabeth is my pride but Margaret's my joy." She holds onto it!

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