Miley Cyrus has recorded a cover of Melanie Safka's track Look What They've Done To My Song, Ma for a new documentary about laws that prohibit women from showing their breasts in public.

The pop star, who likes baring her own breasts, agreed to rework the tune for Lina Esco's new movie Free the Nipple.

Her cover will be played over the end credits of the film, according to Variety.

Cyrus met Esco while filming the comedy Lol, and the director showed her an early version of the film, which is inspired by a phrase Esco coined in 2013.