Hildur Gudnadóttir reunites with director Todd Phillips for the score to Joker: Folie à Deux, following their acclaimed work on 2019's Joker, which earned Gudnadóttir an Academy Award, GRAMMY, BAFTA and Golden Globe. Phillips describes her music as 'basically the second biggest character in the first film', and her return was never in question.

For Folie à Deux, Gudnadóttir pushed her sonic language further, inventing a new instrument to reflect Arthur's internal split. Inspired by his mental confinement, she worked with Icelandic builders to create a 'string prison' - long strings stretched through space and played with a trench cello - to evoke both euphoria and claustrophobia.