Hildur Ingveldardóttir Guðnadóttir (born 4 September 1982) is a classically trained Icelandic cellist who has played and recorded with the bands Pan Sonic, Throbbing Gristle and Múm, as well as her solo project Lost in Hildurness. She has also toured with Animal Collective.
In 2007 she released a solo album, Mount A, on which she attempted to "involve other people as little as I could." It was recorded in New York and Hólar in the north of Iceland. 2009 saw the release of her second solo album, Without Sinking on the UK-based audio-visual label, Touch.
As well as the cello, Hildur also sings and arranges choral music, once arranging a choir for performances by Throbbing Gristle in Austria and London. As a composer she has written a score for the play Sumardagur ("Summer Day") performed at Iceland's National Theatre. She has also written the score for the Danish film Kapringen (A Hijacking).