Thom Yorke on NPR

Goblin's keyboardist opens the feature with the instruction the original director gave him, that the audience must feel the witches are present even when nothing at all is happening on screen. That is why the music begins with a looped lullaby, and why he later added his own voice over the top to make it more unsettling.

Luca Guadagnino saw the film at 14 and describes the music as something like an electric shock. He did not reuse it or go back to its authors because he wanted a particular quality of melancholy and twisted joy, and he says he thought of nobody except Thom Yorke.

Yorke had never scored a film, had turned one down in 1999, and knew his bandmate had made a name as a composer, so he was intimidated. What persuaded him was the director's apparent confidence that he could do it.

The central dance had already been choreographed. After four or five abandoned attempts to write to the movements, he realised he had to disconnect from the dance entirely, go somewhere else in his head, and come back.