Ethel Cain is one of the voices on the soundtrack to Werwulf, Robert Eggers' new gothic-folk horror film. She wrote the song “Wynter Waxeth” with Robin Carolan, who composed most of the score and previously worked with the director on The Northman (2022) and Nosferatu (2024).

The full album is out digitally December 18, with vinyl following January 29 via Sacred Bones. Carolan's title track is available to hear now, while Cain's song closes the 37-track record.

Directed by Eggers and co-written with Sjón, Werwulf puts a new spin on the werewolf tale, following a 14th-century English town haunted by a beast that threatens a man and his family. It stars Aaron Taylor-Johnson, Willem Dafoe and Lily-Rose Depp, and opens in theaters on Christmas Day.

Carolan described the process: “I'd send her medieval music, prayers, weird ambient stuff, and we'd talk through it all. It was one of those rare collaborations where we just seemed to be on the same page about everything.” He said the initial plan was to use Cain's voice in a more textural way on the score, but the two soon began discussing a full song. “She sang the song in Middle English, and with Rob's help she mastered the pronunciation on the hop, practically in one session,” he said.

Cain's most recent album, Willoughby Tucker, I'll Always Love You, came out in 2025, following that year's dark ambient record Perverts.