Demi Lovato is opening up about her past drug use and some of her darkest days in a new interview with "Access Hollywood".

The 21-year-old singer and "X Factor" judge has been open about her struggles with substance abuse, eating disorders and self-harming, but the singer recently revealed some of the great lengths she went through when it came to uslng drugs.

"Something I've never talked about before, but with my drug use I could hide it to where I would sneak drugs," she said. "I couldn't go without 30 minutes to an hour without cocaine and I would bring it on airplanes.

"I would smuggle it basically 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," she said. 

Lovato said she was still able to use drugs even with her sober companions around and people watching her 24/7. The singer said she was able to hide the drugs from the people she was living with.

Lovato, who wrote her memoir "Staying Strong: 365 Days a Year," said she realized she hit "rock bottom" when she was 19-years-old and was" found drinking from a Sprite bottle filled with vodka, nine in the morning."

"When I hit that moment I was like, it's no longer fun when you're doing it alone," she said. "I've really never talked about this stuff before... I don't know if I should be sharing this. I'm young and rebellious and out having fun. it was, wow, I'm one of those people...I gotta get my [expletive] together."

The singer said it was the threat of losing her younger sister that helped her turn to sobriety. In the book Lovato mentioned that her mother, Dianna, her friends and management team held an intervention.  

"The last time that I had an intervention, it was my management, my entire team, manager, lawyers, everyone and my parents coming into a room saying if you don't get sober - my mom specifically said, 'You know, we're going to move back to Texas and you're not going to be able to be around you're little sister,'" Lovato said.

Lovato, who was diagnosed with bipolar disorder while in rehab, also opened up about her past struggles with an eating disorder. 

"It was always there, but then I just acted on it at around 8 or 9 years old," she revealed. "I started overeating, compulsively overeating. I would bake cookies and then eat the whole pan. I went from doing that to being unhappy with my body. I went to just completely starving myself and that turned into throwing up and starving myself and it was just this crazy battle going on inside of me. It got really difficult [and] I would throw up and it would just be blood and it was something that I realized if I don't stop this, I am going to die."

Dianna, who also participated in the interview admitted that she ignored her daughter's problem because she "wanted to believe her when she said everything was fine," but eventually she had to do what was right Lovato's sister, Madison.

After completing her 2010 inpatient rehab stint Lovato said she left with a better "understanding of the challenges her mom was also facing." Dianna also received help alongside her daughter.

"There's too many things to name that I learned about myself... A lot of things happened to me with bullying and just other things that I will touch on later in life when I feel ready to talk about it," Lovato said. "Things that happened that I realized weren't OK and things that I blocked out of my memory or just didn't think they were as severe as they were."