Kiernan posted a makeup-free selfie with her teething son, Michael Francis, one morning, with the caption, "I used to think I knew what exhausted was. Hilarious."
But along with hundreds of comments in support of her relatable mom moment, the news anchor received some snide remarks about her appearance, including one that said, "This doesn't even look like the same person!" Kiernan wrote on Facebook.
"Newsflash! These ARE NOT pictures of the same person," she responded, posting her professional headshot alongside the selfie.
"The woman on the left is well rested, spent two hours on her hair and makeup, had a professional photographer take her picture (and photoshop it, I'm sure), and is in the "glowing" second trimester of pregnancy."
"The woman on the right got two hours of sleep (maybe), hadn't looked in the mirror, took a selfie, did not put a filter on it and is covered with spit up and drool from a teething and very crabby baby."
"You are an idiot if you think these are pictures of the same woman."
Kiernan's comeback struck a cord with fellow moms and other followers, who liked her post 13,000 times and counting.
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"Being a new mommy takes its toll and you are doing great holding down a full time job away from home and a full time job AT home! Keep doing what you're doing and the heck with the haters!!!" wrote another.
Kiernen is just one of many newscasters who has been body shamed by viewers. But like her, many of them have taken down their critics on social media and emerged victorious.