Lili Reinhart. Picture: Instagram.

Lili Reinhart has slammed her critics for calling her body dysmorphia "irrelevant" because she is "skinny".

The 'Riverdale' star is fed up of being criticised for opening about her body issues and having her comments shut down because she's "skinny".

She wrote on Twitter: "Feeling really disheartened by the fact that so many people are saying, 'you're skinny so shut up about embracing your body'. As if my body dysmorphia is irrelevant because of how I look to some people. I'm either not curvy enough or not skinny enough to feel insecure.

"Mental illness gets worse when people say that you don't have a right to feel the way you do. That's where we are failing. Do not encourage this behavior. It is destructive. More destructive than you'll ever realise. You may not understand someone's insecurity- but respect it. (sic)"

Meanwhile, Lili previously insisted she will "never apologise" for her body.

She wrote on her Instagram story: "...Sometimes and unflattering photo is taken of me... My body is something that I will NEVER apologise for. My body will constantly go through change. And so will yours. And that's fine. So let's not put so much time and effort into caring about a stranger's figure."