A decade after Chris Stapleton first served as Guns N’ Roses’ opening act, the country singer joined the band onstage during their Toronto concert this week to perform “Knockin’ on Heaven’s Door.” Stapleton and Axl Rose shared lead vocals on GN’R’s rendition of the Bob Dylan classic, with Stapleton — in town for his own Toronto show Thursday night at Rogers Stadium, the same venue as GN’R’s gig — also providing rhythm guitar as Slash embarked on a lengthier-than-usual solo…..

A decade after Chris Stapleton first crossed paths with Guns N’ Roses as an opening act, the country superstar returned to the band’s world in spectacular fashion this time not from the side of the stage, but standing directly beside…