Charli XCX brings out Halsey for surprise duet at Lollapalooza

Charli Xcx shocked fans by bringing out fellow pop star Halsey for a surprise Spice Girls cover at Lollapalooza festival on Sunday (06Aug17).

After performing a string of hits at the festival in Chicago, Illinois, the British singer asked the crowd, "You guys like girl power, right?" before launching into the first verse of the group's 1996 debut single Wannabe.

She then welcomed Halsey to the stage and fans screamed as she launched into the pre-chorus. The two sung and danced their way through the cover before Halsey gave Charli a kiss on the cheek, hugged her, and ran back off stage.

Halsey had even teased the collaboration on Instagram hours before by sharing a picture of them both laying on a series of cushions in their pajamas and writing in the caption, "I'm not having a slumber party with @charli_xcx but I #wannabe."

Charli shared the same picture and continued to drop hints by writing, "are u ready lolla?? #zigazigahhhhh."

She also posted a picture with rapper CupcakKe, her other special guest, and wrote, "PLUS I HAVE ANOTHER V V V SPECIAL GUEST COMING OUT TOO!!! BE THERE ANGELS!!!!"

After the performance, she shared a picture from backstage with Halsey and CupcakKe and added, "I love these ladiezzzz!!! @iamhalsey @cupcakkeafreakk!!!! Thank u for sharing the stage with me!!!!!!! thank u lolla!!! and thank u to all the angels!!!!!"

Charli and CupcakKe performed a rendition of Lipgloss, a track from her 2017 mixtape Number 1 Angel.

The 25-year-old is going to team up with Halsey once again from September, when she serves as support on the Badlands singer's Hopeless Fountain Kingdom world tour alongside PartyNextDoor. It kicks off in Connecticut on 29 September and runs until November.