In the fall of 1992, despite the fact that his career was riding high on the strength of the No More Tears album, Ozzy Osbourne decided to announce his retirement. He committed to play two farewell shows, Nov. 14 and 15, in Costa Mesa, Calif., and asked his old band, Black Sabbath, to do the honor of opening the shows. But that's not how things worked out.

This plan might have sounded good to Ozzy, and to Black Sabbath guitarist Tony Iommi, but wasn't so appealing to vocalist Ronnie James Dio – who, according to Iommi's autobiography, Iron Man, told the guitarist, "I'm not doing that. I'm not supporting a clown." Dio made his case, then left the band, leaving Iommi to figure out another plan of attack. Enter another powerhouse vocalist from their native Birmingham, England, Rob Halford.

Halford, having recently left Judas Priest behind, gladly accepted the invite to share the stage with Black Sabbath to perform the two concerts. Not surprisingly, he delivered the goods, as you can see above. He would reprise this role again at a concert in 2004, when Osbourne had taken ill.

Osbourne's retirement was short-lived. As it turned out, the reason for his decision – a diagnosis of multiple sclerosis – was a mistake. The reality is that he had a genetic condition called Parkin syndrome, which has similar symptoms. He resumed recording in 1995 with the release of Ozzmosis.

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