Former X Factor winner Matt Cardle has opened up about his battle with addiction and entering rehab last year.

The 30-year-old checked in to The Priory Clinic in London on December 29 in his battle against addictions to alcohol and prescription drugs.

Speaking to The Sun On Sunday after leaving the centre, Cardle revealed the extent of his problem and admitted that his condition was potentially fatal.

"The doctor said to me if I'd been left to my own devices for another three or four weeks I might not be here now," he explained.

"To be told it is life or death, I was like, 'Hold on a minute, how have I come to this? How has it got this bad?'"

Cardle recalled that he first took Valium to conquer his fear of flying, but was soon so dependent on the prescription drug that he became "like a zombie".

"I didn't have my wits about me to even count how many I'd taken. It was a lethal situation. Towards the end I was so out of it I was asking people around me how many pills they'd seen me eat.

"That little word in front of the drug, 'prescription', gave it an air of safety for me. But it's the total opposite - they are so highly addictive both physically and mentally."