Karen O has lent her fantastic, otherworldy musicianship to movie soundtracks before—her unforgettable score for Spike Jonze’s feature film adaptation of Where The Wild Things Are in 2009 will be in the cultural consciousness for longer than most soundtracks are available in stores. Now, she’s teamed with Jonze again for his upcoming Joaquin Phoenix-starring film Her for a song called simply “The Moon Song.”

In the film version of the track, Phoenix and a computer that he falls in love with (yes, you read that right) sing the song in duet, with the (female) computer vocals provided by Scarlett Johansson. It’s a quiet, strummed-down love song, off-kilter and quirky enough to fit into a plot that kooky, but it bears Karen’s signature scruffy soprano against spare acoustics. Stream or grab a free download.