"I am posting this on behalf of young girls, women, and mothers of all ages," she wrote. "I'm enjoying a vacation with my son after a long season of shooting and being away from him for weeks at a time over those months. Since websites and magazines love to share 'celeb flaws' ― well I have them!"
She added, "My body has given me the greatest gift of my life: Luca, 5 years ago. I'm turning 30 in September and my body is healthy and gets me where I need to go. Ladies, lets be proud of what we've got and stop wasting precious time in the day wishing we were different, better, and unflawed. You guys (you know who you are!) already know how to ruin a good time, and now you are body shamers as well."
The actress concluded her caption with the hashtag #kissmyass.
Duff is not afraid to speak out about parenting issues. Back in December, she clapped back at mom shamers who had a problem with her kissing Luca on the lips. In an interview with Redbook earlier this year, she spoke candidly about being a divorced mom, noting that "it sucks."
In a world where so many aspects of motherhood are filtered and glamorized, it's nice to know we can count on some famous moms to keep it real.