Sabrina Carpenter wows Lollapalooza, joins forces with Earth, Wind & Fire for classic hits.

Pop star Sabrina Carpenter surprised Lollapalooza attendees by inviting legendary R&B group Earth, Wind & Fire on stage to perform hits like "Let's Groove" and "September." This marks the second time this summer Carpenter has collaborated with Rock & Roll Hall of Fame bands, having previously performed with Duran Duran in June. Carpenter's upcoming album, "Man's Best Friend," is set to release on August 29.