Rihanna Again! Goes braless, skips underwear, exposes her butt crack at Met Gala afterparty

 Rihanna - What an ass

Rihanna looked über glamorous at the Met Gala in New York City Monday, baring her toned midriff in a white look she co-designed with Stella McCartney. The "Monster" singer, 26, added a touch of sparkle with Jacob & Co. and Dionea Orcini jewels. Rihanna spent the evening hanging out with Kate Bosworth, Cara Delevingne and Reese Witherspoon, all of whom wore bespoke looks by McCartney.

Later that night, however, Rihanna quite literally became the butt of the joke.

For her official afterparty at Up & Down in the West Village, the "Pour It Up" singer changed into a slinky gold dress that featured a plunging back. The braless beauty went commando—a move that would later bite her in the ass. While posing for photographers, she flashed two inches of butt crack.

Whether her racy look was intentional is unknown, but the oft-nude pop star has no qualms about showing some skin. After all, she recently posed topless—exposing her nipple rings—for a LUI cover.

Rihanna promoted the naked photo shoot via Instagram, which is a violation of the social networking site's terms of service. When her account became inactive Monday, fans wondered if the company had shut it down. What really happened? "This account was mistakenly caught in one of our automated systems and very briefly disabled," Instagram told E! News. "We apologize for any inconvenience."

The "S.O.S." singer's account remains inactive as of Tuesday morning. Rihanna has yet to address the issue via her Twitter or Facebook accounts; E! News reached out to her camp for comment Monday.