To celebrate the November 25 release of "Black Sabbath: Live… Gathered in Their Masses", original members Ozzy Osbourne and Geezer Butler made a special appearance on November 6 at the Grammy Museum's Clive Davis Theater in Los Angeles, California. Following a sneak peek at their forthcoming DVD, "Black Sabbath: Live… Gathered In Their Masses", Ozzy and Geezer took part in a question-and-answer session where they shared their thoughts on the band's reunion, their "13" album and the group's critically acclaimed world tour.Video footage of the discussion can be seen below. "Black Sabbath: Live… Gathered in Their Masses" contains footage filmed at the band's April 29 and May 1 concerts in Melbourne, Australia, two of the first shows the group played after completing the recording sessions for "13". The long-awaited disc, the first to feature Osbourne, Butler and guitarist Tony Iommi together in 35 years, earned the group its first No. 1 debut on the Billboard album chart when it arrived last June. SABBATH recently took part part in the South American leg of its "13" tour with support from MEGADETH. Butler, Iommi and Osbourne reunited in late 2011. Original drummer Bill Ward was on board at first but dropped out over contract disputes. Progress on the record was slowed first by Ward's departure and then by Iommi's January 2012 cancer diagnosis. Iommi revealed in September in a post at his web site that he went back into the hospital after the North American tour for more cancer treatment. The guitarist has to be treated every six weeks to keep the disease in check.