The former Disney actress, who continues to battle an eating disorder, hit out at Star for a cover story in which it claimed the wife of Prince William is "gaining mommy weight".
© WENN / Adriana M. Barraza
© Rex Features
Tweeting the image of the slimline royal, Lovato wrote: "So apparently Kate Middleton (William?) is pregnant because of THIS picture... Are you KIDDING ME?!!
"And people wonder why girls/guys have body image issues.. Whether she is or not, she still has a beautiful body. Shame on you Star magazine."
© Twitter/Demi Lovato
Lovato recently accused the TV and film industries of working to "glorify an unhealthy body image" and called for them to "take more responsibility".
The 20-year-old has admitted that she occasionally relapses into her old ways since entering rehab for body image issues and self-harming in 2010.
