Lady Gaga on December 15, 2012 in New York City. Credit: Jackson Lee/

Free Mother Monster!

Lady Gaga found herself behind bars on Dec. 15 when she hit the town in New York City. But the star wasn't locked up in jail -- she was voluntarily encased in a gold cage-like headpiece adorned with chains and bolts.

The bizarre accessory, which looked like a cross between a baseball catcher's mask and Hannibal Lecter's muzzle, topped what would have been an otherwise tame outfit for the "Born This Way" singer: tight black tuxedo pants tucked into lace-up platform boots, and a sheer lace blouse under a leather motorcycle jacket.

Tame, of course, is not in Gaga's vocabulary -- at least, not when it comes to fashion. But she left the face mask backstage when she joined the Rolling Stones onstage in New Jersey later the same night wearing a black, gold, and silver bodysuit with a long blonde wig.

"Thank u for my beautiful suit @RayBrownFashion," she tweeted of her concert outfit. "The stretch velvet combinations summoned the glam gods. I felt like a star."