The iconic frontman recalls a moment in 1986 when the thrash giants were supporting him on tour.
Ozzy tells: "I came past their dressing room, and I had to ask one of their assistants if they were taking the piss out of me, because they were playing Black Sabbath.
"For someone to tell you ‘Black Sabbath changed my life’ is a weird thing to get your head round."
But despite the band's legacy of dark-edged music, Osbourne insists it's all about having fun to him.
"I've never wanted to be serious, to have solemn music," he says. "The way that all that happened with the music and the name and everything, if I remember, is we used to rehearse in a movie theatre. So we decided to write songs inspired by scary movies.
"It was all flower-power and love - but for us, living in the industrial town of Birmingham, we liked scary movies."
Osbourne is at work on his first Sabbath album since 1979 alongside bandmate Tony Iommi, Geezer Butler and producer Rick Rubin. Drummer Bill Ward failed to reach a contractual agreement and bowed out of the original lineup reunion. He recently stated he'd like to be part of Sabbath’s future.
They've written 15 songs, 12 of which are slated to appear on the album, and tracking is well underway. Sabbath haven't revealed its title but have confirmed it's due out in April next year (via ClassicRockMagazin).
They've also announced a four-date tour of Australia between April 25 and May 4. The following week they'll headline the inaugural Japanese edition of Osbourne's travelling tour Ozzfest.