Rolling Stone interview series, Unknown Legends, features long-form conversations between senior writer Andy Greene and veteran musicians who have toured and recorded alongside icons for years, if not decades. All are renowned in the business, but some are less well known to the general public. Here, these artists tell their complete stories, giving an up-close look at life on music’s A list. The latest edition features Deep Purple keyboardist, Don Airey, who has worked with Black Sabbath, Ozzy Osbourne, Judas Priest, Iron Maiden’s Bruce Dickinson, Whitesnake, Jethro Tull, Brian May, UFO, Gary Moore, and many others.

In the following excerpt, Airey discusses working with Black Sabbath...

Andy Greene: Tell me about getting the job to record with Black Sabbath.

Don Airey: "That was actually through Jon Hiseman. As well as running a band, he also ran a PA company called Colosseum Acoustics. And Sabbath used to use his gear. I think Tony Iommi phoned Jon up and said, “We’re looking for a keyboard player. Do you know anybody?” And Jon recommended me. He phoned me up and said, “You gotta be at Morgan Studios tomorrow for Black Sabbath. Don’t worry. They’re very nice people.” But they had a fearsome reputation. Tony had punched a couple of journalists and Ozzy had a reputation for being quite wild.

"I turned up with three or four keyboards. I’d met Ozzy before. When I showed up, he said, “Would you fancy a cup of tea?” I said, “Oh, yes, please.” We sat around having a cup of tea and listening to the tracks. And then off we went. We had a great sessions. I couldn’t believe how good Tony was. What a competent musician he was as a guitarist. He was very versatile."

Andy Greene: It was a weird time for the band. They were about to part ways with Ozzy. Did you sense any of that tension?

Don Airey: "They were kind of falling apart. I remember Bill Ward saying to me, “I don’t know what to do with your man Osbourne. He’s driving us all mad.” Bill was really worried about Oz. It was a bit of a strange time for the band. I think they could feel they were splitting up, but I’m very proud to be on that record. It was a great session."

Andy Greene: Did they talk about bringing you on the tour?

Don Airey: "They asked me, yeah. They were going to America and wanted me to come. But I kind of got wind of the fact that Rainbow were about to come in for me. I didn’t turn them down. I said, “Are you sure? You sound very hesitant about whether you actually want a keyboard player or not.” I just kind of left it and didn’t follow it up with their manager."

Read the complete interview at RollingStone.com.