Metallica is taking part in the annual Bridge School benefit concert this weekend in California, and they had a very special guest join them on stage last night. At the end of their acoustic set, which consisted of ‘Hero of the Day’, ‘Enter Sandman’, ‘Whiskey in a Jar’, ‘Seek & Destroy’, ‘Bleeding Me’, ‘Hardwired’, and covers of The Clash‘s “Clampdown’ and Deep Purple‘s ‘When A Blind Man Cries’, Neil Young stepped on stage with the heavy metal icons to perform a memorable cover of ‘Mr. Soul’ by Buffalo Springfield for the lucky fans in attendance. Check out footage of that historical moment below right now!