Rihanna lets it all hang out. Photo: WENN

While walking around in NYC's Soho today, Rihanna gave some onlookers a prime view of something they didn't expect to see: her nipple ring.

The singer wore a sheer top with no bra, and "covered up" only with an open hooded short sleeve sweater.

We're not sure if Rihanna was inspired by the notoriously braless models at Fashion Week, or simply too busy to realize that she was exposing herself to everyone in sight.

Either way, the star has certainly had better style moments, and at the risk of sounding like her mother -- we just wish she'd keep her goodies under wraps.