From PEOPLE Magazine Click to enlarge
Kelly Osbourne is on her third outfit change of the afternoon at her parents' home in Calabasas, Calif. After a morning of primping in front of a gaggle of photography assistants, makeup artists and a select few of the Osbournes' 16 dogs, a stylist suggests she remove her cardigan, and Kelly delivers a trademark pout. "Please, can you not?" she snaps. She takes a breath and suppresses tears welling up in her eyes. "Sorry, I'm just having a really hard day," she says, returning to her pose.

"She's not comfortable in her skin today," Sharon Osbourne explains later, cozied up with her daughter on the couch in Ozzy Osbourne's library. "In the past, she would have said, 'I have food poisoning, I have to go.' And she would have taken pills. But she stuck with it. This is a huge gold-star day."

Three weeks after returning to L.A. from a rehabilitation center for drug and alcohol addiction, Kelly appreciates the acknowledgment. "This is about being able to be humbled by things," she explains. "I feel like a child again."

At 24, Kelly is embracing the opportunity for a fresh start. Her family's struggles with addiction are no secret: Before getting sober five years ago, her father, Ozzy, 60, abused drugs and alcohol for 20 years (he checked into the Betty Ford Center the day after Kelly was born); brother Jack, 23, was treated for drug and alcohol addiction at 17; Kelly's first stint in rehab was at age 19, followed by another visit the following year. When Kelly moved from her home in London to L.A. last year to host a family variety hour called Osbournes Reloaded on FOX (premiering March 31), she decided to face the addiction she's battled for years. "I can't honestly say I've ever been clean," she says. "I'm getting a second chance, and I want to be present for it."

Getting here hasn't been easy. Growing up, Kelly turned to prescription drugs to numb the depression and anxiety she felt as an adolescent in L.A. At 13, "I had my tonsils taken out, and they gave me liquid Vicodin," she recalls of the first time she used painkillers. "I found, when I take this, people like me. I'm having fun, I'm not getting picked on. It became a confidence thing." Within three years Kelly was easily obtaining pills from friends and doctors. "I have crazy anxiety. I was walking around with a constant sweat moustache," she says. "So what's the first thing you do? Go to a doctor. They give you Xanax, Klonopin, Valium. I'd start off taking them as prescribed. Then I'd be like, 'These are magic pills! Take 10!'" By the time MTV's camera crews arrived in 2002 to create the hit reality show The Osbournes, the family's middle child (elder sister Aimee, 25, keeps out of the public eye) was self-medicating daily with "whatever I could sniff or swallow to not be me."

Media attention towards her weight didn't help matters. "Having your local radio station talking about how fat you are? It really hurt. One Web site put up my phone number telling people to call me and tell me I'd eaten too many doughnuts," she recalls. But when Kelly rediscovered Vicodin, a narcotic pain reliever that can have euphoric effects for some people, her troubles seemed to vanish. "The first time I took a Vicodin pill was at a club in L.A. I felt like the walls were closing in on me. Someone said, 'Take one of these.' Within 45 minutes I was the life of the party. I thought, 'I can take one of these and I don't have to worry about if I'm dressed right or look fat.'"

Despite her family's history of addiction, matriarch Sharon, 56, says she was in denial about her daughter. "I always give them the benefit of the doubt," she says, tearing up. "Even though in the back of my head, I kind of know it, in my heart, I don't want to say it." Meanwhile Kelly used Ozzy's then-ongoing addictions to divert attention from herself. "I'd be like, 'Look at Dad! It's him, not me [who has a problem]. You're just projecting on me now.'" (Ozzy Osbourne was unavailable for comment.)

Though struggling personally, at the peak of her addiction, Kelly was thriving professionally. In 2002 her debut album, Shut Up!, reached No. 1 on Billboard's Heatseekers charts; in 2005 she released the record Sleep in Nothing. But touring worsened her problems. "On tour you're alone, in a foreign country where you can't speak the language." By 2005, Kelly admits, she had sabotaged her career: "I drank, I was rude, I said I'd do something and wouldn't show up. I did what I could to destroy it."

Kelly's parents caught her with prescription drugs in 2004 and sent her to Promises Treatment Center in Malibu. She was relieved—but not rehabilitated. "Promises works for some people; for me it was too comfortable. It was like a vacation without a bar," she recalls. She returned to rehab in 2005 but didn't stay clean. Living in London for the next three years, Kelly had high points: She landed roles in TV and theater, and through her work in fashion (she modelled for designer label Heatherette) she met model Luke Worrall, 19; they became engaged last November. "I had good months and bad months," she says.

Last January, with Worrall in London, Kelly returned to L.A. to film Osbournes Reloaded. Being alone—and back where her drug use had been at its worst—triggered an intense relapse. "So many people get sober in L.A., but it's really hard for me. I know where to hang out where people will just offer you drugs. Everyone does it here," she says. Soon, her depression spiraled. "I couldn't see into tomorrow. I was using anything to make me sleep through the day. I got really into smoking pot. My only relationship was with the pizza delivery guy," she says. "It sounds funny in retrospect, but it's not funny that I hated myself like that." Her biggest regret? "It's so embarrassing, the number of times I've thrown myself down the stairs to try and hurt myself to get pills," she says. When her family and friends demanded that she get help, "I knew if I didn't go, I would die. I thought, 'Thank God someone's going to make this pain go away.'"

Treatment during her 30 days at a rehabilitation facility included therapy sessions with her family and a weeklong visit from Worrall. "I learned a lot about myself," she says. "If I'm anxious, I have to take certain steps in letting people know I suffer from anxiety. If I'm uncomfortable, I can take a break and call someone to help me, rather than sit there, exploding." Her family, including Worrall, "learned how they can help me progress in a healthy way."

Clean for the three weeks since she left rehab, Kelly is living in L.A. with Worrall for now and adjusting to a different outlook on life. "Getting up in the morning and not having to think of a list of lies is a new thing," she says. "I went on a plane and didn't take a pill for the first time."

Another thing she's handling carefully? Wedding plans. Ozzy and Sharon said the young couple can't have their blessing to tie the knot for another five years. "Neither of them is ready for domestic bliss right now," says Sharon. Kelly says she and Worrall agree rushing ahead would be foolish: "I'd become one of those cracked out housewives with a vacuum cleaner, hopped up on Dexedrine!"

Soon she's laughing, a long overdue burst of joy for a girl who doesn't always find it easy to keep smiling. "I have to take every day as it comes," she says. "This is a disease. I was born with it. I'll die with it." But she's cautiously optimistic. "I just want to be happy," she says. "Anything is better than the way it was."