A mum received a note body-shaming her for wearing leggings. Her response is the classiest.

A woman who received an anonymous letter shaming her for wearing leggings has hit back at bullies with a message of body positivity.

Florida mother Kelley Markland, who enjoyed wearing “fun” leggings, returned home from a birthday dinner in November to find a distressing letter in her mailbox.

The scrappy handwritten note told her,”Women who weigh 300 pounds should not wear yoga pants!!”, which she found along with an image of a woman bending down in a supermarket and a cruel meme.

The 36-year-old took to Facebook to respond, telling the letter's author they had made her "feel like absolute, complete sh-t".

"Anyone who knows me, knows that I care deeper and stronger than many. I am a sensitive woman and I despise cruelty towards others," she wrote.

"I have never pretended to be pretty or look good in clothing, I have never tried to be flashy or show off.

"Wearing my "fun" leggings gave me a tad bit of confidence in not looking sloppy all the time. I'm sorry that some of you may not like it, but I'm not dressing for you."

The substitute teacher said she was in disbelief at the bully's choice to send her a letter.

"All the hate in this world, and you have to pick on me for this?! Thank you for making me feel like absolute, complete sh-t."

"A wonderful night with my family had to end like this.....so unbelievably disappointed in people anymore."

Despite the rock to her confidence, Ms Markland went to the school where she worked the next morning wearing her leggings.

And she wasn't the only one. Parents and mums at the school had read the post and wore their leggings as a sign of solidarity.

"I had to remember, if I walked around defeated and scared, then whoever sent that letter wins. And I wasn’t going to let that person win. At all," she told the US Today show.

"All the teachers were coming up and hugging me and showing me their leggings. So I knew at that point, it’s not about me anymore, it’s about all women.

"[The response has] been amazing and mind blowing. It’s so inspiring to have other people telling me that what they’re doing now is because of this little act of bullying."

Ms Markland has also sent a defiant message to her haters with her new profile picture.