@kpsg2 / Twitter 1 / 9
@kpsg2 / Twitter 1 / 9

A piggy-tailed Katy Perry spent Monday "dipping low" to the sounds of rumored boyfriend Diplo in Las Vegas.

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That she was seen again with the electronic music DJ and producer at XS Nightclub isn't really surprising. Her outfit, on the other hand, is more of a head scratcher.

"She was twerking and wearing a leather surgical mask," an onlooker said. "She also had light-up neon sneakers. The only reason I even noticed her at all is because she was twerking. I walked closer, saw her eyes and hair and was like, no, it can't be. Then the mask slips down ... I saw all the security around and knew for sure."

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Her attendance at his Vegas DJ set would seem to confirm that things are still "on" for the duo who were first spotted together in April but have managed to keep a fairly low profile. Last month, Perry, 29, and the 35-year-old Diplo, aka Thomas Pentz, dismissed rumors of a breakup when they posted Instagram photos on seemingly the same hammock while on a tropical vacation.

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The beginning of their relationship came on the heels of her umpteenth breakup with John Mayer.