Katy Perry performs during a fundraiser for Democratic presidential candidate Hillary Clinton. (Andrew Renneisen/Getty Images)

Hey, isn’t that… pop star Katy Perry, chilling with pals at the Alex in Georgetown into the wee hours of Sunday morning?

A spy tells us that the “Roar” singer/Hillary Clinton backer — chic in loose hair and dangling statement earrings — appeared to be part of a post-wedding party. The happy gang lounged on the patio, snapping pics and sipping cocktails.

Turns out that the lounge, which is in the Graham hotel, was a good location for star-spotting: Our tipster also caught sight of Ben Feldman at the bar with a few friends. Less surprising to see him out in the DMV than Perry: The “Mad Men” actor is a Potomac native and still visits the ‘rents there.