WATCH: Charli XCX Brings Out Halsey For Spice Girls Cover

Things got a little spicy on Sunday during Charli XCX’s Lollapalooza set in Chicago.

Asking if the crowd like “girl power,” the pop star started performing the Spice Girls 1996 hit “Wannabe” — and then brought out surprise guest Halsey.

The duo, who were clearly performing to vocal tracks, even did some Spice Girls dance moves.

MORE: Charli XCX Puts Famous Friends In "Boys" Video

Charli XCX is one of the warm-up acts on Halsey’s upcoming tour in support of her new album Hopeless Fountain Kingdom.

The tour plays Montreal’s Bell Centre on Oct. 3 and Toronto’s Air Canada Centre on Oct. 4 and then stops in Vancouver on Nov. 11, Calgary on Nov. 14 and Edmonton on Nov. 15.

Check out Charli XCX and Halsey at Lollapalooza: