Speaking to Willow Smith, Adrienne Banfield-Norris and Jada Pinkett-Smith on a podcast, Osbourne opened up about her heroin addiction during her teens. She said that it was cheaper than "pain pills".
"I kept getting sick and I had a really bad case of tonsillitis", she said.
"They ended up having to give me some crazy surgery and then after that they gave me Vicodin and that was all I needed".
Kelly also revealed that she was just 13 years old when she was given Vicodin, which began her drug addiction.
"It went very quickly from Vicodin to Percocet to Heroin eventually because it was cheaper", she said.
Kelly, daughter of Sharon and Ozzy Osbourne also added, "I went from having every voice in my head going like, 'You're fat.' 'You're ugly.' 'You're not good enough.' 'No one likes you.' 'You don't deserve this.' 'People don't like you because of who your parents are".
"And all of a sudden, every single voice was silenced and it felt like life gave me a hug".
In another interview, Kelly revealed she relapsed in April.
This month the singer also said, “I went away somewhere with my friend and people were by a pool, they were drinking champagne".
“It was champagne and it was like, ‘I can have a glass of that".
She continued, "And I had a glass and I was fine, walked away from it, didn’t have another one for a couple of weeks, didn’t even think about it".
“And then I was out with my friends and I was like, ‘I’m going to have a drink, I’m fine. I had two drinks, I was fine".
“And then it started off from going having one drink here, one drink there to literally three bottles of champagne and 24 White Claws a day”.
Kelly Osbourne has also previously dismissed rumours that she has undergone plastic surgery.
"I want to make something very clear. I am not a liar. I have never had plastic surgery. At least not yet!!!!", she said.
“The only thing I had done [was] a bit of Botox in my forehead and jaw", she admitted. "And I had my top lip injected. That’s it".
She also revealed to having gastric surgery last year, resulting in a weight loss of 85 lbs.
