Demi Lovato has slammed “harmful” retouching apps.

The ‘Anyone’ hitmaker has hit out at people who take photos of celebrities and put them through apps that alter their appearances to make them fit current influencer aesthetics, as she says the programs “reinforce impossible beauty standards” and can be “harmful” to the celebrity involved.

She fumed on social media: “sometimes fan art can seem harmless, but be careful if you’re constantly editing your idol’s pictures. Reinforcing impossible beauty standards onto your favorite actress/singer/model not only rude, dumb, & harmful to your own beauty standards and ideals. (sic)”

Demi, 27, also shared more context from a journalist named Danae Mercer, who posted before and after pictures of celebrities who have had their images retouched, including Margot Robbie, Cameron Diaz, and Anne Hathaway.

In the post which Demi shared, Danae wrote: “PHOTOSHOPPING accounts are popping up EVERYWHERE - making already stunning celebrities ‘MORE BEAUTIFUL’ or transforming pieces of art to fit today’s FACETUNED AESTHETIC.

“Be careful on the internet.

“Be careful when looking at the world through a lens that is filtered in so many, many ways.

“The images of the FACETUNED CELEBRITIES feels jarring. The same goes for the ‘enhanced’ art. But we see these kinds of edits every. single. day.

“Be careful with your heart, Your mental health, And the content you consume.

“Because YOU are wonderful. You are amazing. And you, my dear, deserve to believe it every single day. (sic)”

Meanwhile, Demi previously opened up on her battle with an eating disorder, which began when she kept seeing “really skinny celebrities” and thought she needed to look like them.

The singer also struggled with addiction and self harm, and said she hopes to be the kind of role model for young people that she herself didn't have when she was growing up.

She said: "I grew up in the era of really, really skinny celebrities. That was the look. And it was cool to be seen partying. Drugs were glamorised, and when I was 12 or 13, nobody [I looked up to] was talking about mental illness. Nobody was talking about eating disorders. Nobody was talking about cutting. I wanted somebody for my little sister to look up to. I took on that role because I knew it was important."