The guest parade continued Friday night when Metallica hit the stage of San Francisco's Fillmore Theater for the third of four special concerts there to celebrate the band's 30th anniversary. Following two other star-studded gigs earlier in the week, Metallica were joined onstage this time around by Judas Priest singer Rob Halford, Danzig / Misfits frontman Glenn Danzig and Lynyrd Skynyrd's Gary Rossington.

Fridays night's 21-song setlist touched on all eras of the band's career and featured a handful of covers, including songs by Lynyrd Skynyrd, Blitzkrieg, the Misfits (with Glenn Danzig) and Judas Priest (with Halford). Other guests over the course of the gig included Alice in Chains guitarist Jerry Cantrell, Down's Pepper Keenan and Anti-Nowhere League's Nick "Animal" Culmer.

Metallica also premiered another unreleased song, unveiling the 'Death Magnetic' outtake 'Hell and Back.' The previous two concerts saw the live debut of 'Magnetic' outtakes 'Hate Train' and ‘Just a Bullet Away.'

For more on the concert, including the complete setlist and a slew of live video footage, click here. Metallica play their fourth and final 30th anniversary concert tonight at the Fillmore -- perhaps James Hetfield's dream of being joined onstage by Ozzy Osbourne and Motorhead's Lemmy Kilmister will finally come true.

Watch Metallica Perform the Previously Unreleased Song 'Hell and Back':