The 33-year-old, who gave birth to her son Jonathon in March 2016, shared a photo of home-made jean shorts she’d cut to replace her pre-pregnancy ones.
“There is no shame in gaining weight during pregnancy (or ever),” she told her followers.
“There is no shame if it takes longer than you think it will to lose the weight (if you want to lose it at all).”
Hathaway continued: “There is no shame in finally breaking down and making your own jean shorts because last summer’s are just too dang short for this summer’s thighs.
“Bodies change, bodies grow, bodies shrink, it’s all love. Don’t let anyone tell you otherwise.”
The actress’ fans praised her for the body positive post.
“You are such an inspiration, Anne!” one person commented. “Well done!”
Another wrote: “Beautiful! Thank you. I am sharing this with my beautiful and very pregnant daughter.”
Hathaway confirmed she was pregnant in January 2016 after realising the paparazzi were trying to get photos of her bump.
She shared an Instagram photo of herself in a bikini.
“I figure if this kind of photo is going to be out in the world it should at least be an image that makes me happy (and be one that was taken with my consent and with a filter),” she wrote.