There's nothing quite like the massive onslaught that comes with pulling a musical together. I've made a lot of records, collaborated with different singers and worked on music for television and movies, but nothing prepared me for writing songs for musicals.
Although I'd worked on the musical version of Barbarella, an extremely complicated project by virtue of being all in German, working on Ghost (in English) still felt like mastering the Rubik's Cube; sometimes you need to write songs that propel the story forward, sometimes songs that get an emotion across, and sometimes the songs have to weave in and out of each other.
The success of the original 1990 movie was down to its story – it's so emotional and compelling. When I was approached by the producers and asked to write the songs and music for a musical version, I thought it was absolutely crucial to have Bruce Joel Rubin, who wrote the original screenplay, on board.
I didn't want to be making something that wandered too far from his original story; a story which is ultimately about how important it is to understand the moment you're in, to not be crushed by whatever it was in your past that stops you from being able to share your love. I wanted that to remain intact, and I think it does.
Having met Bruce and found him to be a lovely and interesting man, I said that I would love to get involved and decided to bring my good friend, Glen Ballard on board too.
As a result, the sound and feel of the music in Ghost is a mixture of Glen and me. Does it sound like any of my other work? There are definitely sections where you can hear that I have tipped my hat to certain elements of my musical past. During the New York bank scene you can hear Eurythmics-style electronica mixed in with real string players.
Thinking about it, musicals are what got me into music in the first place. When I started to play the guitar at 13 or 14 years old it was all about Bob Dylan, of course. But my interest in music really began when I was around four or five years old. I remember that my father built a sort of radiogram that went all over our house. He took some wooden speakers and wired them up in the corners of my bedroom and my brother's bedroom, as well as in the kitchen and the living room.
Although we lived in a terraced bungalow in Sunderland, the day he switched on these little wooden sound boxes, the whole house became a magical place. Every single morning before school, we'd listen to music, loud and clear.
And the music he played was always from musicals: The King and I, The Sound of Music and The Flower Drum Song. Before I had ever seen the movies or the plays, I used to stare at the album covers and imagine them. Then when I was around seven or eight years old, I remember seeing South Pacific for the first time on the screen and being gobsmacked. I spilled my sweets and popcorn all over the floor.
When it's done well, putting music and theatre together can be transfixing. I would very much like to continue experimenting with music and theatre, bringing new ideas to it and collaborating with great people. I'm wary, though, because the collaborative experience on Ghost has been so great. With such a great team working on such a compelling story, I think we have created something really quite unique.
'Ghost: The Musical' , Piccadilly Theatre , London W1 (0844 871 7618) to 28 January