Ozzy Osbourne wasn't "allowed" to have fun in Black Sabbath.
The 'Paranoid' rock star has hit out at his band, and insisted guitarist Tony Iommi's control meant he didn't get the same joy out of performing that he does with his solo act.
He explained to Rolling Stone: "With Sabbath, all I am is a singer with a band. This is a different thing. I've got a lot of freedom and I have fun with it... It's not allowed to have f***ing fun with Sabbath.
"It's too serious. Tony was trying to have a go at me, saying, 'Don't f***ing talk over my solos.'
"I go, 'OK, are you sure? 'Cause most of the f***ing song is solos. The intro to the song is f***in' five minutes and then I sing for about two seconds and then it's another one.' "
However, as the frontman of his solo project, the 69-year-old star gets the chance to relax and "get the crowd going".
He added: "With my own thing, I'm looking to have fun, and that's what music's about for me.
"I'm not a serious f***ing singer. I'm just a frontman who's trying to get the crowd going in front."
For now, Ozzy is off the road after cancelling tour dates due to a hand infection which meant he had to undergo surgery.
He's already excited to get back on tour, and recently said: "I was really looking forward to doing the Hollywood Bowl. I'm going to make those shows up next year. It could have been a lot worse. I could have been dead."
Now visiting a specialist once a week - initially it was three visits each week - Ozzy doesn't expect to feel like his old self, but he revealed he is "well on the mend".
He added: "To be honest with you, I didn't feel that bad all along. I said to the doctor at one point, 'When can I work out?' He said, 'You can do whatever you like, but I don't advise you to for at least 10 days.'
"I tried working out for two minutes and I thought I was gonna f***in' die, because the antibiotic knocks the wind out of your sails big-time. So I went, 'You know what? I'll let the doctor be the doctor and I'll be the patient.'
"So now compared to what I was like, I feel about 85 to 90 percent better. So I'm well on the mend."