"I've been working so hard to get healthy and fit," Demi tweeted. "I can't believe I'm about to do this but I'm so excited.. Here's my bikini time body!"

Lovato, who announced she was quitting Disney Channel's Sonny With a Chance last month, added that the picture was partly the result of her new outlook on life.

"I never thought I'd ever feel confident enough to ever do that. I'm excited how far I've come since being completely ashamed of my body," she added. "I want any girl/guy out there who struggles with body image or confidence to know that it IS possible to find peace with yourself. It hasn't been easy, but it starts with a commitment to yourself. . .your mind. . .and your soul. And trust me, I'm still working at it! Haha."

Sounds like she's doing great. Congrats, Demi!