Big dances numbers, including the best waltz this side of Christoph, layer the film with dizzying swirls of colour and music. Big fish, little fish, cardboard box wouldn't wash in this company, so Belgian choreographer Sidi Larbi Cherkaoui was recruited to give the cast six weeks intensive dance coaching. Dario Marianelli's score was largely completed before shooting, making the union of music and dance easily the happiest marriage in the movie.