When you're filming in Russia in Catherine's Palace, and you're in the real place where the Tsar's ball really happened, all those years ago, it does so much of the work for you. It's so vivid. You escape into this different time through the costumes, the sets and the atmosphere.

I love clothes but it's a struggle for me to get out of jeans and a baggy jumper.

Helena (Bonham Carter) is one of the coolest kindest women I've ever met. We had so much fun. She has the best sense of humor. I loved her fairy godmother. It came at a point during night shoots where I was exhausted. It was trippy, weird and cold ... and then Helena showed up. It was like this bright light on the horizon; it was wonderful.

I think that period dramas just need zombies.

Playing a Disney princess is the most amazing, unbelievable thing and on the other, it's completely terrifying. I would say it's a cocktail of every sort of emotion. Princesses are great role models, they teach you about grief loss and have big hearts.

I think it's probably best to work out in the morning to get it out of the way. My ultimate top tip is to drag yourself, even if you have to roll yourself out of your bed and in to a sit-up - it's really not that bad once you start.

Boarding school in Tring was a bit of a bubble that burst when I went to Hackney to go to drama school.