Demi Lovato feels beautiful just the way she is, thank you very much.

The 19-year-old singer fought back at critics who ridiculed her healthier, curvier figure on Twitter during Sunday's MTV Video Music Awards.

VIDEO: Watch Demi's triumphant return to the stage

"Guess what? I'm healthy and happy, and if you're hating on my weight you obviously aren't," Lovato, who wore a plunging Mandalay mini-dress, wrote.

Twilight actress Ashley Greene, 24, sent Lovato a message of support, reminding the "Skyscraper" singer that she's "beautiful."

PHOTOS: Demi Lovato through the years

"This is why you're my friend," Lovato responded. "Thank you girl."

PHOTOS: Stars who were bullied for their weight

Bullied for her weight as a kid, Lovato developed an eating disorder that turned into a lifelong struggle with food. "That's kind of what I've been dealing with ever since," the singer admitted on 20/20 earlier this year. "I was compulsively overeating when I was eight years old. So, I guess, for the past 10 years, I've had a really unhealthy relationship with food."

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