On Sunday, the 44-year-old actress tweeted to her followers: "If you've been sexually harassed or assaulted, write 'me too' as a reply to this tweet."
The tweet also included another message that was "suggested by a friend," which reads: "If all the women who have been sexually harassed or assaulted wrote 'Me too' as a status, we might give people a sense of the magnitude of the problem.
The social media movement quickly took off, with celebrities and fans alike sharing their stories. Debra Messing, Ali Fedotowsky-Manno, Evan Rachel Wood, Sophia Bush and Anna Paquin all replied to the tweet, writing: "Me too."
Hamilton star Javier Munoz also responded to Milano, writing: "I don't know if it means anything coming from a gay man but it has happened. Multiple times."
In addition to the "Me Too" movement, Milano penned an op-ed for Patriot Not Patriotism in response to the numerous allegations of sexual harassment and assault against Harvey Weinstein, including Milano's Charmed co-star, Rose McGowan, who alleges that the movie mogul raped her.
"This is a sick culture. Men like Harvey Weinstein are around every corner. Men who undermine women and their strength, ability and intelligence exist everywhere," she writes. "Statistics say that 1 in 3 women are sexually harassed in the workplace. Really think about that. Really allow that statistic to become a part of you."
The Mistresses star concludes: "Please know that I fight for women's rights every day. I am constantly part of this conversation even if I don't publicly comment on specific scandals. Sexual harassment and assault in the workplace are not just about Harvey Weinstein. We must change things in general. We must do better for women everywhere."