Sabrina Carpenter had a surprise trick up her sleeve during her headlining set at Lollapalooza in Chicago on Sunday night (Aug. 3). The “Manchild” singer wowed the massive crowd gathered around the T-Mobile main stage — while A$AP Rocky did the same on the opposite end of the park on the Bud Light stage — by treating them to a special mini-set from R&B legends Earth, Wind & Fire.

“And we can just let loose, right? We can just groove,” Carpenter, wearing a sparkly pink jumpsuit with her name across the chest said as the strains of EW&F’s 1981 Billboard Hot 100 No. 3 disco pop classic, “Let’s Groove,” bubbled up behind her. “So I thought, ‘why not bring out my friends from Chicago?’ Give it up for Earth, Wind & Fire!” she screamed as members of the iconic group joined her on stage to sing the song’s familiar refrain.

“Let this groove, get you to move, alright/ Let this groove set in your shoes, stand up, alright,” singer Philip Bailey crooned in his signature falsetto. Carpenter spun in circles and shook it out to the song’s familiar funk pop groove, mouthing along and then joining in on the “move yourself and glide like a 747” verse with a gigantic smile on her face as she doubled up Bailey’s vocals on the chorus.

The mini-set also featured a run through EW&F’s perennial fall classic and 1979 Hot 100 No. 8 smash “September,” with a bright brass assist from the band’s horn section. “I’m gonna join the band, guys!” Carpenter enthused after the unexpected collab. Sunday’s Lolla lineup also featured sets from Mariah the Scientist, Remi Wolf, Finneas, Dominic Fike and Martin Garrix.

Carpenter’s upcoming seventh studio album, Man’s Best Friend, is due out on Aug. 29, with the singer revealing the full track list last week with some help from an adorable golden retriever puppy.

Check out footage of Carpenter and EW&F at Lollapalooza below.