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

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!

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

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.

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

That external struggle mirrors the struggle of this life force of energy that [princess Margaret] was.

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