I`ve gained weight, get over it, says Demi Lovato

London: Demi Lovato has hit back at critics who commented on his weight gain, insisting they need to "get over it".

"I`ve gained weight. Get over it. That`s what happens when you get out of treatment for An Eating Disorder... Guess what, I`m healthy and happy, and if you`re hating on my weight you obviously aren`t," Lovato posted on micro-blogging site Twitter.

Lovato underwent three months of treatment for a series of emotional issues, including an eating disorder, earlier this year.

The 19-year-old has since gained a fuller figure which received negative comments online, reports contactmusicom.