Charli XCX is heading out on tour with Halsey next month, and during her set at Lollapalooza today, after asking the crowd if they liked Girl Power, she brought out the alternative music artist to help cover the Spice Girls classic “Wannabe.” (Halsey was not otherwise scheduled to perform at Lollapalooza.) Charli also confirmed that her recent bop “Boys” comes from a forthcoming album, in case anyone was worried she wasn’t going to make albums anymore. Watch their performance below.