Ozzy Osbourne feels his wife Sharon's workload could kill her.

The Black Sabbath frontman, who briefly separated from the 'X Factor' judge earlier this year after relapsing into drink and drugs, says he fears for her health as much as his.

The 65-year-old told The Sun newspaper: ''I don't know anyone who can fly 11 hours, get off the plane and go straight to the studio. She must have a bit of astronaut blood in her or something.

''When she was doing that Apprentice thing [in America in 2010] I was dumbfounded. She'd get up at four in the morning despite having the worst f***ing cold ever.

''I was like, 'Are you joking? Get back in bed! But she went to the set, worked 'til whatever time. She's going to die.''

He said his wife's battle with colon cancer in 2002 was a difficult time for the whole family and they thought they were going to lose her after she was given a 33 per cent survival rate.

But despite chemotherapy having ''knocked the sh*t out of her'' she started running again when she ended her treatment and went straight back to work.

The legendary hell-raiser continued: ''Is it all worth it? Nothing is worth killing yourself for. There comes a time when I think I'm sick of lying down over this. I don't understand it.''

Sharon, 61, was said to be ''very p***ed off'' when Ozzy fell off the wagon, which he calls the ''lost weekend'', and she threatened to end their 32-year marriage if he didn't get clean.

He's now been sober for nearly a year and the couple - who have three children together Aimee, Kelly and Jack - are looking forward to spending Christmas in their Buckinghamshire mansion.

Ozzy added: ''I've done so much sh*t in my life, I'm lucky to be alive. I'm also lucky to have Sharon because she puts up with so much. I've been a bad guy.

''When I don't drink, everything's fine with us. Now, we're okay again.''