Charlie Puth is refusing to let body shamers get him down after finding himself being ridiculed for going shirtless in California.

The Attention singer was photographed without a top on during a gym trip in Santa Monica last week, prompting critics to ridicule Puth for his lack of a muscular physique.

Hitting back at the cutting comments, he took to Twitter and wrote, "Hey just a very quick reminder that it's not cool to body shame anyone. Not entirely sure what the purpose of it is. Sorry I don't have an 8 pack like damn......"

Fans were quick to come to his defence, with many insisting his body is "perfect" the way it is, but Puth proved he hadn't taken any of the haters' remarks to heart as he took to Instagram on Monday and shared an early morning selfie, showing off his curly locks.

"Good morning!!! I hope you have a SEXY Monday....I know I will," he captioned the shot.

Puth is known for calling out body shaming in the past, having previously highlighted the dangerous message advertisers send to impressionable youths after spotting a commercial for a body contouring photo app.

"I was just watching some video on YouTube and saw this ad come up," he tweeted back in 2019. "An ad directed towards teenage boys & girls insisting that they can contour their bodies to make them look skinner. Some of the renderings don't even look human. Like...what is wrong with this girls body (sic)?! NOTHING."