Jessica Chastain is joining the chorus of celebrities taking aim at Hollywood's gender-bias pay gap for women. The acclaimed actress praised Jennifer Lawrence for recently publishing an essay on how she will no longer stand for taking wages at a lower level than her male costars and plans to negotiate aggressively, despite how male executives routinely shame women for demanding competitive salaries.

"I'm proud of her," Chastain told Variety on Wednesday at the premiere of "Crimson Peak." "Sometimes when you’re doing well, you're afraid to say something's wrong because then there's going to be a bunch of people out there going 'OK, well, you're a big old movie star.' But it doesn't matter."

Continuing, the "Martian" actress added: “There’s no excuse. There’s no reason why she should be doing a film with other actors and get paid less than her male costars. It’s completely unfair. It’s not right. It’s been happening for years and years and years. I think it’s brave to talk about it. I think everyone should talk about it."

“What I really appreciate is that it’s not just women,” said Chastain. On Wednesday Bradley Cooper, Lawrence's costar in "Silver Linings Playbook" voiced his support for his onscreen partner. The Oscar-nominated actor, who played opposite Lawrence in “American Hustle,” reportedly negotiated a higher salary than the in-demand actress Lawrence in the hit heist flick, taking in 9% of proceeds from the film versus her 7%, according to an email leaked after a cyber attack on Sony earlier this year. In fact, leaked correspondence revealed that costars Christian Bale and Jeremy Renner all received higher salaries than Lawrence.

In Lawrence's candid essay published on Lena Dunham's Lenny blog, she expressed regret for acting demur during contract negotiations because she feared earning an unwarranted reputation of being a “brat”–something she said she believes is perpetuated by showbiz male executives who continue to pay women unfairly.

She wrote: “I didn’t get mad at Sony. I got mad at myself. I failed as a negotiator because I gave up early. I didn’t want to keep fighting over millions of dollars that, frankly, due to two franchises, I don’t need. (I told you it wasn’t relatable, don’t hate me).”

However, she added in the op-ed that she’s moving forward more relentlessly to demand what she’s worth. “I’m over trying to find the ‘adorable way to state my opinion and still be likable! F— that,” she wrote.