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

It was always said you couldn't have two sisters less alike. In a way [princess] Elizabeth was always internalizing everything and [princess] Margaret was always externalizing everything, so that became the basis. The storyline becomes about these two sisters: they're fighting for their position or trying to establish their identity in the world alongside each other and in relation to this establishment which only those two were a part of.

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

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

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.

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.

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.