Lorde surprise-attended a fan party in Sydney, performing new music disguised as a DJ.

New Zealand pop star Lorde surprised fans by unexpectedly attending a themed party dedicated to her at Sydney's Mary's Underground on May 25. Disguised, she joined DJ Emma Parke on the decks, singing her new song "What Was That" and her collaboration with Charli XCX, "Girl, So Confusing." The event was reportedly her idea, as she prepares to release her new album, "Virgin," on June 27.