Ozzy Osbourne was responsible for Tony Iommi discovering he had cancer in 2012, Black Sabbath bassist Geezer Butler recalled.

The incident took place as the band was working on its final album, 13, after announcing plans for one last record and tour in 2011. In his new memoir Into the Void (excerpted in Rolling Stone), Butler discussed how the project collapsed into a “soap opera” that included drummer Bill Ward’s withdrawal.

“As writing was in process at Ozzy’s house, he made the observation that Tony had lost too much weight and that he should get checked out,” Butler noted in his book. “When Tony got back to England, he was diagnosed with a form of lymphoma.

"If I’d been diagnosed with cancer, I’d have canceled everything and stayed at home for the rest of my life. But Tony’s not like that. When me and Ozzy flew to England to resume writing, Tony would have chemotherapy in the morning and come straight home to his studio, where we’d put some ideas together.”

He noted that Iommi was “tired and nauseous” and “his hair was falling out” as a result of cancer treatment, but the guitarist “was determined to plow on, just like he did when he lost the tips of his fingers.” While the guitarist was in no state to tour, the band arranged a one-off show headlining the 2012 edition of the U.K.’s Download Festival, which Butler said had proved “there was plenty of life in the old dogs yet.”

Butler recently expressed his respect for Ward’s refusal to be part of Sabbath’s final years in a part-time capacity. In the book, the bassist reflected, “I was upset that what should have been a triumphant return for the original lineup had turned into a bit of a soap opera – and [I] ended up making it worse. While Bill was churning out public statements, Sharon [Osbourne] was giving me her side of the story, including that Bill had refused to play a charity gig at Birmingham’s O2 Academy.

“Stupidly, I then put out a statement on the internet, including a line about Bill wanting money for said charity gig. I regret doing that because I’d ended up doing the band’s dirty work. Worse, I’d betrayed Bill’s friendship by not believing his side of the story, which was that he’d actually agreed to do the charity gig for free.”

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