There's nothing quite like when two of the biggest pop stars on the planet unexpectedly unite on stage, but when it's to offer up a large serving of 90s nostalgia, well that's just dreams coming true.

Charli XCX brought out PAPER cover-girl Halsey during her Lollapalooza set this weekend to take Spice Girls "Wannabe" and frankly, it was magical from start to finish. While Charli's next project won't drop until 2018, she's certainly been coming in hot lately, recently dropping the video for her latest single "Boys" — filled to the brim with cameos from celebrity friends.

Check out the duo doing their thing below.

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[h/t The Fader]