Sabrina Carpenter brought out a special guest to perform a Nancy Sinatra classic at Outside Lands 2024.

During her headlining set at the San Francisco festival on Saturday (Aug. 10), the 25-year-old pop star welcomed Kacey Musgraves for a surprise performance of Sinatra’s 1966 hit “These Boots Are Made for Walkin’.”

“She won’t come out unless you’re very loud,” Carpenter told festival-goers. “We look so good, oh my God!” she added after Musgraves arrived. “Should we sing our song?”

From there, the two stars traded verses while Carpenter kept the tempo on tambourine. Musgraves sported a form-fitting silver dress while Carpenter donned a dark sparkly miniskirt with matching high heel boots.

“These Boots Are Made for Walkin’” was penned by Lee Hazlewood, and Sinatra’s recording was released in December 1965. By February 1966, it had reached the top of the Billboard Hot 100.

Prior to her set, Carpenter took a sip from an espresso cup to celebrate her smash hit “Espresso” surpassing 1 billion streams on Spotify. The track reached No. 3 on the Billboard Hot 100 chart in April and topped Billboard‘s Pop Airplay chart last month.

This year’s Outside Lands also featured headlining sets by the Killers and Sturgill Simpson, and will include a special country set by Post Malone on Sunday night. Carpenter replaced previous Saturday night headliner Tyler, the Creator, who dropped out in late June citing personal reasons.

Watch Carpenter and Musgraves perform “These Boots Are Made for Walkin’” on X (formerly Twitter) here and YouTube here.