Black Sabbath guitarist Tony Iommi didn't just make a guest appearance on Ozzy Osbourne's upcoming 13th solo album, he and the Ozzman co-wrote the track on which Iommi performs.

The collaboration marks the first time the Hand of Doom and the Prince of Darkness have written together since Black Sabbath's final album, 13, which was released ahead of the band's farewell tour last decade.

Iommi revealed the extent of the collaboration in a new interview with Rolling Stone, revealing that he "wrote the whole track and played on it and played the solo on it."

"It's good," he continued. "It's really good. And I like what Ozzy sang on it. I think he did a really good job. And I think they had Chad [Smith] play drums on it. I've left it in their hands now."

Iommi and Ozzy communicate regularly via text, the guitarist added of their post-Black Sabbath relationship. He says the pair mostly cut out phone calls because Ozzy forgets about the time difference between where he lives in Los Angeles and where Iommi lives in England.

"I think we stopped [voice calls] when he used to phone me at 2 o'clock in the morning and I'd go, 'Oz, it's 2 o'clock in the morning.' [He'd say] 'Oh, oh, sorry. Alright. Bye.'"

In addition to Iommi's song on the new album, Ozzy secured guest performances from guitar heroes Jeff Beck and Eric Clapton. His longtime bandleader Zakk Wylde returned to the studio to record most of the rhythm guitars on the record, while Metallica's Robert Trujillo (who played with Ozzy from 1996 - 2003) completes the rhythm section with Smith on drums.

Ozzy has yet to announce a release date for the new album, though it's expected to arrive sometime in early-2022.

Studio X