When I read Room I just absolutely fell in love with the characters of Jack and Ma and the voice Emma had created of this child who was so unknowing about the world in so many ways and yet so wonderfully inquisitive. It was such a beautifully vibrant character. And Ma as a female character I thought was just a brilliant, strong, survivor.

But as soon as I read the book I could hear songs in my head. Very often when I start to get an idea for a show it starts with a piece of music. I don't intend that, it's just the way my brain works, So I started hearing these songs. I was on tour with another another show at the time and I very quickly went to my hotel room and started jamming out some songs.

I approached Emma four years ago, before the film. I had a very clear idea in my head. I described the music to her and it really was a gamble. I thought 'Oh my God, here's this woman with this incredibly popular, brilliant piece of work and some director she's never heard of is telling her it could be a musical or a play with songs'. But I believed in the idea so much that I sent her some really rough demos, and gave her the idea that I wanted to avoid it in any way being a gratuitous, voyeuristic, sensationalist drama. It would all be from the perspective of Jack, as it is in the book.

I described the idea I had for a set too. Whenever Jack went inside the wardrobe, which he does every night, the set would rotate so we would go inside the wardrobe with him and we would only see what he sees through the slats. And that's the set we've ended up with. I think she liked that. She got that I understood where the perspective of the story was. And we're using a lot of projection to get inside Jack's visual imagination. We're using drawings by real five-year-olds which have been animated.

Emma has come on a long journey with Room as well. She knows where I'm coming from. She knows about the background to all the ideas. She was so incredibly open. She wasn't precious about the novel. It was a lovely two way process.