Pop star Demi Lovato has revealed that she was once so addicted to alcohol and drugs that she would sneak cocaine on to aircraft.

In a raw and revealing interview with Access Hollywood, the 21-year-old American X Factor judge admitted that at the height of her troubles she struggled to last more than a an hour without using.

"I couldn't go 30 minutes to an hour without cocaine and I would bring it on airplanes," she said.

"I would smuggle it and just wait until everyone in first class would go to sleep and I would do it right there.

"I'd sneak to the bathroom and I'd do it. That's how difficult it got, and that was even with somebody [with me]. I had a sober companion, somebody who was watching me 24/7, living with me. I was able to hide it from them as well."

The former Disney actress confessed that during her darkest days she would manipulate people and tell lies to conceal her battle with drugs.

"I'm very, very good at manipulating people and that was something that I did in my disease, I would manipulate everyone around me," she said.

"There were times I would just continue to lie, so that everything looked OK on the outside."

The Heart Attack singer said she received her wake-up call when she was took a Sprite bottle to the airport filled just with vodka at nine in the morning .

"I think at 19 years old, I had a moment where I was like, 'Oh my God... that is alcoholic behaviour. [It's] no longer, I'm young and rebellious and out having fun, it was, wow, I'm one of those people... I gotta get my s*** together.'"

In October 2010, the songstress, who now leads a sober lifestyle, abruptly withdrew from the Jonas Brothers' Live in Concert tour to enter rehab for "physical and emotional issues".

Her mother, Dianna de la Garza, said she had an idea that her daughter was doing drugs but "for a long time I was in denial".

"It's like any other parent, when you see things you don't want to believe - that's what's actually going on. So when they're telling you that's not what is going on you want too badly believe them. For a long time I was in denial."