Demi Lovato has opened up about the time she was doing drugs. The Sorry Not Sorry singer has said that she almost choked to death after taking a "bunch of coke" and a few prescription pills.

"My heart started racing, and I thought to myself, 'Oh my God, I might be overdosing right now," the 25-year-old revealed in her documentary Simply Complicated, according to The Daily Mail.

The songstress did not stop using drugs even though she was temporarily placed on psychiatric hold following the death scare.

"I would sneak out and get drugs," she said and added that she went on to fake drug tests using "other people's pee".

Lovato, who had a relapse in 2012 following her rehab stint in 2010 for alcohol and drugs dependence and therapy for an eating disorder and self-harming, also said that she used to smuggle cocaine onto planes.

"I wasn't working my programme, I wasn't ready to get sober. I was sneaking cocaine on planes. I was sneaking it in bathrooms, sneaking it throughout the night," she said. "I went on a bender of like, two months where I was using daily. I was using while I had a sober companion, and I went through about 20 different sober companions."

What made Lovato stop the substance abuse? She gave it up as the thought of losing the people she cared about started to scare her.

"The most important thing to Demi is losing people, losing people that she cares about and that love her," Lovato's sober coach Mike Bayer said.

Lovato's manager Phil McIntyre said: "I worked with everyone on the team — business managers, agents, attorneys, everybody, to say, 'If Phil walks, we walk."

"This was the showdown of all showdowns," he added.

Lovato said, "It's embarrassing to look back on the person that I was," and added "I think that approach worked for me because ... it was the beginning of the process of surrendering."