In the past three and a half decades, there have been various Black Sabbath lineups, and Osbourne has also had a successful solo career since the release of 1980's Blizzard of Ozz. There was an attempt in 2001 by the original members to record an album with producer Rick Rubin but it came to nothing. Now, sufficient water has passed under the bridge to make them – minus Ward – eager to make it work. It still felt, Rubin has said, "like being in a cage with a lion, keeping them calm", but the results, they agree, were worth it. 13 sounds more like Black Sabbath than any album since 1973's Sabbath Bloody Sabbath. Osbourne says 13 is the most important record of his career.

"Yes, we've had our disagreements," he says. "We all said bad things and did our different trips, but it's great to be with the guys. The last time [2001] it didn't gel. But this time it worked out better than our wildest expectations. For Tony to come up with riffs like these is unbelievable. He deserves a medal because if I'd been diagnosed with lymphoma I'd have gone 'Fuck this', and gone back to bed with a bottle of morphine. But we kept on going because we knew this was probably our last hurrah.&