EXCLUSIVE: Osbournes Talk With '20/20'

Sept. 10 -- In an exclusive interview with Barbara Walters, Sharon and Jack Osbourne discuss just how bad things got for their famous family during the past year.

Watch the full interview on 20/20 this Friday at 10 p.m.

Speaking with extraordinary candor, Sharon reveals for the first time that she briefly left husband, Ozzy, when Jack's addiction forced him into rehab. While waiting for a bed to open up for Jack, Sharon says Ozzy continued to abuse prescription drugs and alcohol. "I just said, 'you just have to stop,' and he didn't. And I said, 'well then I'm going.' And I packed my bags, and I left."

The separation lasted just a few days, she says. "The minute I left, the next morning, he gave up drinking. But I needed to make sure that he was on a roll. That he really meant it. And, after four days, I came back to see him. And he was trying so hard. So hard. Still is clean and sober."

Jack Attempted Suicide

Jack, 17, talks about the depths of his addiction to alcohol and pain killers, including OxyContin, and depression about his mother's colon cancer. Jack admits that his depression was so severe he attempted suicide.

"I attempted to overdose … take a whole bunch of pills and drink some absinthe," he says. "You know, I remember speaking to my friend one time, and he looked at me, goes, 'you know, what are you going to do if your mom does die?' And I said, probably just kill myself."

School Regrets

Sharon maintains that her family's experiences are not unusual. "Things just don't happen to us. They happen to other people, too. Other people have cancer, other people have husbands who are addicts, children that are addicts. And we never said we were perfect. I am far from perfect. I'm like the biggest mess-up I know."

Sharon says she has some regrets about decisions she's made for her children. In a 2002 interview with Walters, Sharon confidently defended her decision to allow all three of her children to drop out of school, saying they were learning enough in the school of life. Now, Sharon says, she thinks that's the biggest mistake she made with her kids.