U2 sign up as Leonard Cohen's backing band

U2 have taken a break from their sell-out US tour to provide backing to revered crooner Leonard Cohen in a tiny Manhattan, New York club.

The group were filmed recording Cohen classic Tower of Song at cabaret lounge The Slipper Room yesterday for an upcoming documentary about the torch singer.

Ironically, U2 star Bono performed Cohen's Hallelujah on tribute album Tower of Song a decade ago.

Bono sings a verse of Cohen's hit while U2 provide back-up for the track, which will feature in the untitled Lian Lunson film.

Bono and bandmate The Edge join Jarvis Cocker and Nick Cave among the stars paying tribute to Cohen in the film.