Anne Hathaway is focusing on the all-important #GAINZ rather than what haters think. She reiterates her position with a snappy Instagram post.

It's Not Me, It's You

The Oscar-winning actress posted a video of her hardcore workout on Instagram on Thursday night, letting fans know that's she in the process of gaining weight for a role and couldn't care less what they think of her changing body.

"I am gaining weight for a movie role and it is going well. To all the people who are going to fat shame me in the upcoming months, it's not me, it's you. Peace," wrote the Devil Wears Prada star.

The short clip shows the 35-year-old lifting weights, doing sit-ups, push-ups, squats, and calisthenics in a form-fitting leotard. Easily keeping up with the routine, Hathaway is clearly in the midst of getting properly jacked.

A cheeky P.S. alerted followers to her continuing sense of humor about her looks, though, as the Oscar-winner noted she wanted to use Queen's ode to body positivity, "Fat Bottomed Girls," but it was copyrighted.

The actress didn't specify which role required such in-gym dedication, but she was recently confirmed to have taken over from Amy Schumer in the upcoming, live-action Barbie film.

No Stranger To Criticism

This isn't the first time Hathaway has altered her body significantly for a part. Her Oscar-winning role in Les Misérables required her to drop a whopping 25 pounds to play starving prostitute Fantine.

Appearing on Tuesday's Today show, Hathaway opened up about her recent weight gain.

"I'm living in my body and I'm happy with my body ... If my body is different than what you're used to, or what you think it should be, that's yours. And my experience is mine and I'm loving it," she explained.

The Ocean's 8 star also admitted, when pressed by host Hoda Kotb, that she's fat-shamed constantly in real life. She noted, however, that things are slowly changing.

"A lot of us are looking at the language that we choose and we're becoming more conscious about it. ... [We] are taking up this opportunity to become more conscious and more loving in the way that we communicate with each other," she said, referring to her personal experience of being told not to gain any more weight upon scoring a role at just 16 years old.

Hathaway currently has one child, 2-year-old Johnny, with husband, Adam Shulman.

She told Glamour recently that she shared with fans about gaining weight for a role to avoid any pregnancy rumors that might arise as a result of her changing body.