Tonya Wise/London Ent/Splash News Online
03/19/2009 at 05:00 PM EDT
Three weeks after completing a month-long stay
in a rehabilitation center, Kelly Osbourne tells PEOPLE that she's been addicted to painkillers since she was a teenager.
"I had my tonsils taken out [at age 13], and they gave me liquid Vicodin," the TV personality recalls of her first use of 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."
Osbourne, 24, says that despite two trips to rehab in 2004 and 2005, she has never been clean until now.
The star, who reunites with her family for a March 31 FOX special called Osbournes Reloaded
(their first collaboration since MTV's The Osbournes
), decided to seek help after suffering an intense relapse this year. Using downers to sleep through the days, she says, "I knew if I didn't get help, I would die."
"I'm getting a second chance [at my career]," she says, "and I want to be present for it."
For more on Osbourne's battle with addiction – and why she is planning a long engagement to fiancé Luke Worrall – pick up this week's PEOPLE, on newsstands now