(Cover) - EN Showbiz - Demi Lovato has taken steps to defend herself over her recent weight gain.

The 19-year-old singer attended the MTV Video Music Awards last night in a figure hugging dress but had evidently received negative comments online.

She took to her Twitter page to hit back at those saying hurtful things to her, especially as she was released from a rehab facility earlier this year.

"I've gained weight. Get over it," Demi lashed out. "That's what happens when you get out of treatment for AN EATING DISORDER."

The subject is a sore one for Demi who was in rehab for a number of issues including her relationship with food.

She then decided to be more positive about the situation and wrote a more upbeat message on the social networking site.

"Guess what, I'm healthy and happy, and if you're hating on my weight you obviously aren't," she said and added a smiley face with the hash tag #UNBROKEN.

Demi also apparently bumped into her ex-boyfriend Joe Jonas at the event but the run-in was said to have been friendly.

She is releasing her new album on September 20 which she says is more "R&B and pop". (C) Cover Media