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

In his new memoir, “Into the Void,” Butler says 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.

He explained, “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. When Tony got back to England, he was diagnosed with a form of lymphoma.”

Butler went on to say, “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.”