Contactmusic quoted Kelly as telling BBC Radio 5 Live: "I don't have any shadow of a doubt that addiction is a disease. It is in your genes. "The only people in my family who don't have that gene are my mother and my sister Amy."
"I consider myself lucky that I saw both sides of it. Drugs stop you from screaming on the outside, but you are still screaming on the inside. I was addicted by 16. Drugs stopped me from feeling a certain way. Some people experience euphoria but I never felt that. They numbed me and gave me confidence. It was like a magic medicine."
The 24-year-old Kelly has been in rehab four times and is presently drug free.