The Fosse/Verdon star joined Speaker Nancy Pelosi and other members of the Democratic Women's Caucus on Capitol Hill on Tuesday, where she gave a speech in honor of Equal Pay Day.
While speaking to the crowd, Williams recalled what it was like when she discovered that her All the Money in the World co-star, Mark Wahlberg, was making significantly more money than her ($1.5 million vs. $1,000) on reshoots for the 2017 film, directed by Ridley Scott.
"It's the kind of story I would normally resist: the morality tale with a happy ending, or rather a happy beginning, because that's really why I'm here," Williams said. "There won't be satisfaction for me until I can exhaust my efforts ensuring that all women experience the elevation of their self-worth and its connection to the elevation of their market worth."
"In late 2017, the news broke that I'd been paid less than $1,000 compared to the $1.5 million that my male counterpart had received for the exact same amount of work," she added. "And guess what, no one cared. This came as no surprise to me, it simply reinforced my life-learned belief that equality is not an inalienable right and that women would always be working just as hard for less money while shouldering more responsibility at home."
Williams continued on, revealing that she felt "paralyzed in feelings of futility" when she discovered the massive disparity. "I've been a working actress since the age of 12," she explained. "I've been accredited by my industry at the highest levels and that still didn't translate to equal compensation. Months passed and the actress Jessica Chastain, with whom I had in fact played sisters, offered to take my story to her Twitter."
"Jessica's audience was much wider than mine, and she wasn't afraid to pick up a megaphone and be heard. Heard she was, there was an uproar and a public shaming within my industry that resulted in a $2 million donation to the Time's Up Defense Fund," she recalled.
As previously reported, Wahlberg donated his $1.5 million earnings from All the Money in the World to the Time's Up organization's legal defense fund in Williams' name last January, telling ET in a statement at the time that he "100 percent supports the fight for fair pay." His agency, WME, donated an additional $500,000.
"It didn't take much to make the decision," Wahlberg told ET. "It was just the right thing to do, you know? And Michelle is a fantastic actress."
"It's not me who decides who gets paid what," he added, addressing his critics. "Your value's based on what the marketplace dictates, and with that particular situation, it was very awkward."