Ozzy Osbourne said in an interview on the Broken Record Podcast that there is only one member of the original Black Sabbath who can't be replaced -- and it's not him, drummer Bill Ward or bassist Geezer Butler, but guitarist Tony Iommi.

Ozzy explained, "Geezer's a great, great lyricist -- nobody can touch him. Bill, in his day, was a great drummer. Tony, he's always gonna be the greatest -- no one can touch him . . . He was the band, really. We were all part of the band, but he was the most irreplaceable one."

Ozzy added, "Tony, he's one of the few people who could walk into this room right now and I would f**king feel intimidated. He intimidates the f**k out of me -- and he knows it."

The Prince of Darkness told us a while back that he was in awe of Iommi when the latter was going through cancer treatments in 2012 and 2013: "My hat goes off to him 'cause he really is Iron Man. I mean, that chemotherapy knocks you sideways, you know. I mean, when my wife had cancer a few years back, she was having three chemo things a month and it would knock the life out of -- literally every time she'd have a treatment, she'd have a seizure. It's scary stuff. But he came down, plugged in and carried on. He's my hero, I swear to God he is."

Ozzy, Iommi and Butler reunited in 2012 to record a new album together for the first time in 35 years. Titled 13, the disc became Sabbath's first Number One album. The band later played a farewell tour that ended in February 2017.

AUDIO: BLACK SABBATH'S OZZY OSBOURNE ON TONY IOMMI WORKING THROUGH TREATMENT