The Brit model posted this photo to her Instagram account on Thursday night and revealed a diagram of his and hers nipples complete with nifty annotation.
The pressing question is, who is the guy Cara's posing next to?
Aside from the mystery around her man, it's no surprise that Cara is backing this campaign. The supermodel is all about self expression after all - and this photo has already ranked up a cool 204,000 plus likes.
While the guy's nipple is fully on show or should we say "free", Cara's is "censored" to follow Instagram's rule that states a female nipple must be covered up.
Love this cause? Its website explains, "The issues we're addressing are equal rights for men and women, a more balanced system of censorship, and legal rights for all women to breastfeed in public."
Follow @FreeTheNipple on Twitter to show your support.
LOVE CARA'S KOOKY STYLE? Take a look through this gallery to see stunning looks from the 21-year-old Brit model.
MORE! Catch up on all the latest news on Cara Delevingne right here in the video below.