Hildur Ingveldardóttir Guðnadóttir (born 4 September 1982) is an Icelandic musician and composer. A classically trained cellist, she has played and recorded with the bands Pan Sonic, Throbbing Gristle, Múm and Stórsveit Nix Noltes, has collaborated with Sunn O))) and toured with Animal Collective. In 2020, she won the Academy Award for Best Original Score for her work on the film "Joker". In 2006, she released a solo album under the name Lost In Hildurness, Mount A, on which she attempted to "involve other people as little as I could.