As you likely already know, this past weekend featured the final two shows of Metallica's 30th anniversary celebration at the Fillmore in San Francisco.
Among the guests on hand were members of the recently reunited Black Sabbath, Ozzy Osbourne and Geezer Butler, who joined Metallica for renditions of "Iron Man" and "Paranoid." Butler also sat in with the band "Sabbra Cadabra." You can watch videos of all these performance below.
Black Sabbath will be hitting the studio in 2012 with producer Rick Rubin to record their first album featuring their original lineup since 1978's Never Say Die!