Bradley Cooper Stands by Jennifer Lawrence Over Equal Pay in Hollywood: 'There Is a Double Standard'

The actor tells ET, 'I love strong women.'

As Jennifer Lawrence speaks out on the gender wage gap in Hollywood, at least one of her American Hustle co-stars is standing by her side.

Bradley Cooper spoke with ET on Tuesday, the same day that Lawrence's op-ed -- titled "Why Do These Dudes Make More Than Me?" -- hit the web.

WATCH: Jennifer Lawrence Breaks Silence About Being Paid Less Than Her Male Co-Stars in 'American Hustle'

"There's a double standard in the whole world, yeah, for sure. This is just one aspect," Cooper said while promoting his new film, Burnt, which reunites the actor with his American Sniper co-star, Sienna Miller. "Anytime there's a place where a voice can come out and be outspoken -- something Sienna did, or Jennifer -- that's great. ... I think it is making a difference."

Earlier this year, hacked emails from Sony Pictures revealed that Lawrence was paid significantly less than her male co-stars (Christian Bale, Jeremy Renner and Cooper) in the film American Hustle.

"When the Sony hack happened and I found out how much less I was being paid than the lucky people with dicks, I didn't get mad at Sony. I got mad at myself," Lawrence, who won her first Oscar in 2013 for Silver Linings Playbook, wrote in her essay. "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."

She added that, "I didn’t want to seem 'difficult' or 'spoiled.' At the time, that seemed like a fine idea, until I saw the payroll on the Internet and realized every man I was working with definitely didn’t worry about being 'difficult' or 'spoiled.'"

WATCH: Jennifer Lawrence and Bradley Cooper Reunite in 'Joy' -- And She's Got a Gun! 

Today, Cooper says he's glad Lawrence is making her voice heard. "I love strong women," he said. "That's a very attractive thing."

Miller has her own unique perspective on the gender pay gap in entertainment. The actress revealed just last month that she turned down a Broadway gig because she was offered "less than half" of what her male co-star was to receive.

"I feel like [women] won't get those jobs unless they capitulate, and that's the truth," Miller told ET on Tuesday. "I don't think it's diva-ish to expect if you're doing the same job as someone to be paid the same thing. ... I understand the different value of people commercially, but what it means if you do start to fight back is that you will not get that job. And if you love that job and you're passionate about it, that's a really hard thing to relinquish.

"But it's going to take sacrifice, it is," she continued. "It's not about the money, it's the principle."

NEWS: Sienna Miller Opens Up About Being a Single Mom 

Fellow feminist Emma Watson also voiced her support for Lawrence on Tuesday, tweeting, "O Jennifer Lawrence I love you so," and quoting a line from Lawrence's op-ed.

O Jennifer Lawrence I love you so. X

— Emma Watson (@EmWatson) October 13, 2015

"I’m over trying to find the “adorable” way to state my opinion".

— Emma Watson (@EmWatson) October 13, 2015

In September of last year, the Harry Potter star delivered a powerful speech on the floor of the UN to launch a new gender equality initiative. HeforShe advocates for total equality between men and women without the use of negative rhetoric, while encouraging men to join the cause. See the moment in the video below.