Sharon Osbourne said her son Jack's diagnosis with multiple sclerosis has made her "even more of a control freak" than before.
The former X Factor judge and wife of legendary rocker Ozzy Osbourne said her son was doing "great" since he was diagnosed with the illness.
She said: "He's determined not to let this stop the way he lives his life. He's taking care of himself physically and mentally."
But she admitted it had an effect on her, saying: "You go through the guilt, you go through the, 'Is it me, was it me?', and you go through the family tree going, 'Who died of what? Where did this come from?'
"I've become even more of a control freak. I think I'm driving him nuts. He's got a headache and I'm all, like, 'Go to the doctors. I'll drive you myself'."
Sharon, who stepped down from the X Factor in 2008 after four years as a judge, said her relationship with show supremo Simon Cowell was "like brother and sister".
She said: "We row, then we make up. We love each other, then we fight, then we love each other, then we fight. But you know, one of the first people to reach out to me when Jack was diagnosed with MS was Simon. And that meant very much to me. Because it meant maybe he loves me, just a little bit."
The star, who joined Louis Walsh at Judges' House in Las Vegas this year, said her big regret after leaving the X Factor was not getting the chance to work with "those bonkers boys" Jedward.
She said: "I love them - they're bonkers. They've done really well. I'd have had fun with them."