John Mayer’s tour stopped through Nashville on Thursday evening (Aug. 8), for a marathon set that spanned his versatile catalog. His nearly three-hour show also included a special surprise guest: Chris Stapleton.

Midway through his set, Mayer told the sold-out audience at Bridgestone Arena that he had a friend in attendance who would be joining him on stage. He teased the collaboration before revealing his special guest.

"I texted this friend and I said, 'You wanna do one of your songs or one of my songs?' And he said, 'We could do either or we could just write a song and play it.' I said, 'Challenge accepted,'" Mayer said before inviting Stapleton to the stage as the arena erupted in screams.

Mayer also revealed that he came to town early to pen the new song with Stapleton the day before.

The two singers then launched into the brand new track, "I Just Remembered That I Didn't Care," trading vocals and guitar riffs throughout the three-minute tune. Following the performance, Stapleton stuck around to assist on Mayer’s “Slow Dancing in a Burning Room.”

Mayer launched his 2019 World Tour in Albany, New York on July 19. The “Evening with John Mayer” includes two sets from the singer that span his career of hits. The North American dates run through September.

Watch Mayer and Stapleton's collaboration of "I Just Remembered That I Didn't Care" below.