Watch Britney Spears Perform 'Slumber Party' in Las Vegas for First Time

Even while performing night after night for her Las Vegas residency, Britney Spears makes sure to switch it up. Wednesday night, for example, marked the live debut of her song "Slumber Party" from Glory.

Costumes consisted of nighttime silk robes, but her dance moves were far from sleepy. Days ago, Spears and Tinashe shared a remix of the track and promised the video will drop Friday.

Until then, check out fan-shot footage of the "Slumber Party" performance below.: