A legendary farewell. Black Sabbath reunited for Ozzy Osbourne’s final show with the band at Villa Park in Birmingham on Saturday, and the electric concert featured performances by other rock legends.

Ask most music fans who “invented” heavy metal and they’d likely point you in one direction: Black Sabbath. The group’s self-titled debut album was recorded more than half a century ago, in – according to guitarist Tony Iommi – a single day in 1969.

Those who were at the event or watched the livestream likely noticed that Black Sabbath drummer Bill Ward, 77, took his shirt off during the group's final performance. Now, Iommi has revealed a humorous story about Ward's habit and what the band members had to say about it.