Miley Cyrus is no stranger to flashing her bits but now it's for a good cause.

The singer has whipped out her Wrecking Balls on Instagram to back a movement for women's equality.

The #freethenipplecampaign is against the notion that men can walk around with no shirts on but women have to stay under wraps.

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Miley posted an arty black and white shot of her topless with the less-than-arty caption: "Some lame a** deff gonna flag dat s***but f********k it #practicewhatchupreach #FreeTheNipple #freedats***."

The #freethenipple protests took place this past summer and received the backing of Scout Willis, Chelsea Handler, and Miley.

Free The Nipple campaigners say they are fighting for the rights of women to go topless in public.

It has now become a film and according to Fader, director/co-writer and star Lina Esco has worked her real struggle into the script.

She said: "Everything has been so tough. We've worked against all odds - from people not taking it seriously because of the title, to record labels turning us down for music licensing."

(Image: mileycyrus/Instagram)

Miley's topless pic seems to have been removed from Instagram but she has followed it up with other posts ranging from the sublime to the ridiculous, including odd pics with her face as a child pasted on.

Miley posted a link to the film's website which states: "Inspired by true events, FREE THE NIPPLE follows a group of young women who take to the streets of New York City topless, to protest the archaic censorship laws in the United States.

"Activist Liv and With set out to start a movement and change the system through publicity stunts and graffiti installations while armed with First Amendment lawyers.

"The film explores the contradictions in our media-dominated society, where acts of violence and killing are glorified, while images of a woman's body are censored by the FCC and the MPAA. What is more obscene: Violence or a Nipple?"