Ozzy Osbourne has yet to release what he calls his "Sgt. Pepper" album, after the influential 1967 effort by the Beatles, Sgt. Pepper's Lonely Hearts Club Band. That's how rock's reigning "Prince of Darkness" described his notional "ultimate" album in a recent interview.

He said it during a new "Ozzy Speaks" segment on Sirius XM Radio's Ozzy's Boneyard, which aired last month (Nov. 29) in conjunction with the release of the musician's career-spanning See You on the Other Side box set. Watch that portion of the interview toward the bottom of this post.

"I've said I haven't released what I consider my Sgt. Pepper," Osbourne explained. "You know, my ultimate… So when people say, which is my favorite album? I say I haven't made it yet."

The conversation centered around the massive vinyl box set's 173 songs culled from the singer's 11 studio albums. But that doesn't mean Osbourne is ready to rest on his laurels, as the musician paraphrased to co-hosts Billy Morrison and Jose Mangin with a story about his son.

"You know what? My son said to me; he says, 'Dad, why are you always so content with what you've achieved?'" Osbourne added. "But if I go, 'Wow, I've done 173 songs!' I can't take it."

But whether he's truly content, the rocker still has something to celebrate. "Under the Graveyard" — the musician's first new song in nine years — hit No. 1 on Billboard's Mainstream Rock chart this week.

That tune was soon followed by the Slash-aided "Straight to Hell," and Osbourne's twelfth album Ordinary Man is due out early next year. On top of that, his rescheduled European tour dates have appeared.

Ozzy Osbourne Appears on Ozzy's Boneyard - Nov. 29, 2019

Photos: Ozzy Osbourne Through the Years