Axl Rose and Slash of Guns N’ Roses perform during Glastonbury Festival 2023 on June 24, 2023 in Glastonbury, England. (Leon Neal/Getty Images)Attendees of Guns N’ Roses’ concert in Toronto on Wednesday might’ve felt like they were “Knockin’ on Heaven’s Door” when Chris Stapleton made a surprise appearance. The country star joined Axl Rose and company onstage to perform GN’R’s classic cover of the Bob Dylan song, which they recorded for 1991’s Use Your Illusion II album. Stapleton sang backup vocals and strummed a guitar for the nine-minute rendition. Stapleton is set to headline the same Toronto venue, Rogers Stadium, on Thursday night.