A fitness blogger had the perfect clap back for online trolls who were "mom-shaming" her for posting a picture in a bikini.

Sia Cooper, who has over a million followers on Instagram, fired back at a person who slammed the mother-of-two for wearing a bikini and showing her "backside."

“To show your gains you don’t have to show your behind like that,” read a comment. “You are a mother, think about what your children see your behind in your posts in the future. Unfollowed.”

Cooper, who was fed up with online critics, decided to shut them all in a lengthy post once and for all.

The nurse-turned-personal trainer shared the woman’s comment along with a picture of herself in a bikini writing how she had posted it earlier but was told to cover up because she is a mother.

“Since when were moms supposed to hide their bodies? Since when were mothers no longer allowed to feel sexy? How do you think babies even got here in the first place?” she wrote.

Instead of making her kids look down upon her body, Cooper said she wants them to “see a mother who is body positive and confident in her own skin.”

“Plus they love my butt and use it as a bongo when I’m cooking dinner or awkwardly standing in line at the grocery store,” she joked.

Taking a firm stand for all the women, especially mothers, Cooper said there’s no rule out there that states you can’t rock a bikini "just because you pushed a baby out of your vagina." “It can be harder to celebrate our bodies when they’re covered with streches marks and loose skin,” she wrote.

She further opened up on how she grew up with a mother “who hated her body” and in turn made Cooper also hate her own body by "nitpicking it apart".

Cooper ended her post on body positivity by urging mothers everywhere to “feel themselves” and wear whatever they want without fearing society’s opinions.

“Let the mom-judging stop,” she concluded. “Motherhood is already tough as it is, we are damned if we do, damned if we don’t- so stay true to yourself.”

Mother and child A mother and child are pictured on Apr. 16, 2017 in Bahrain, Bahrain. Photo: Getty Images