The 21-year-old TV star, the son of rocker Ozzy and Sharon, is convinced he abused drink and painkillers because he inherited the genetics from his wild dad who has battled drink and drug addictions all his life.
He said: "I blame genetics. Because dad was an alcoholic, that's why I am." Jack was sent to a rehabilitation clinic by his parents to be treated for alcoholism and an addiction to the prescription painkiller OxyContin in 2003 when he was just 17.
The young star admits he turned to both substances to try and cope with mum Sharon's gruelling battle with colon cancer.
He explained: "My problems peaked when mum was sick and dad was dealing with his problems the same way as I was, by drinking, so I had no one to turn to.
I was just hanging out with my crowd drinking and doing drugs." Jack and Ozzy are now both sober and Sharon's cancer is in remission.