Last month, Demi Lovato released a candid book about her past struggles with drug addiction, called Staying Strong: 365 Days a Year. But it seems she wasn't done speaking out. In a recent interview, Lovato revealed that her addiction was so severe that she would sneak cocaine onto airplanes.

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

She added, "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.

"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 and living with me and I was able to hide it from them as well."

The X Factor judge also said that addiction transformed her into a very manipulative person, who became an expert at hiding her problems from others.

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

And her condition rapidly worsened, despite many attempts by well-meaning family members and friends. "I had all the help in the world, but I didn't want it," she said.

Fortunately, these days Lovato is in an entirely different space and she's never been busier or more prolific. In May, she released her fourth studio album Demi, then appeared on another season of X Factor. And now her book is officially a New York Times Bestseller.

Props to Demi for overcoming her demons and being brave enough to share her story with the world.

Demi is definitely one badass chick; check out our celebratory playlist in her honor.

Plus, Demi's growth and evolution wasn't always just on the inside. Check out some of her best and craziest hair moments: