By Meghan Overdeep
Jan 03, 2018 @ 7:45 am

Natalie Portman has finally joined Instagram, but don't expect filtered selfies and #tbts from the Oscar-winner anytime soon—she's on a mission.

Portman shared seven posts on the photo-sharing app this week, all of which promote Time's Up, a new anti-harassment action plan supported by a who's who of powerful women in show business, including Reese Witherspoon, Eva Longoria, Emma StoneKerry Washington, Shonda Rhimes, and more.

"Time’s up on silence. Time’s up on waiting. Time’s up on tolerating discrimination, harassment or abuse. Sign the solidarity letter & donate to the @TIMESUPNOW Legal Defense Fund," Portman, 36, captioned her first post, which outlines Time's Up's mission statement.

Natalie Portman / Instagram

"We seek equal representation, opportunities, benefits and pay for all women workers, not to mention greater representation of women of color, immigrant women, and lesbian, bisexual and transgender women, whose experiences in the workforce are significantly worse than their white, cisgender, straight peers," the post reads.

Natalie Portman / Instagram

According to The New York Times, Time’s Up is leaderless, run by volunteers and made up of working groups. The group published an open letter signed by hundreds of women, that ran as a full-page ad in the paper and the Spanish-language newspaper, La Opinion, on Jan. 1. Portman also shared a screen-grab of the letter, titled "Dear Sisters" on her Instagram.

RELATED: Natalie Portman Has Experienced Workplace Sexism for "Almost Everything" She's Ever Done

Additionally, Time's Up is encouraging women to wear black at the Golden Globes on Sunday, to raise awareness about their initiative.

“This is a moment of solidarity, not a fashion moment,” Longoria told the Times. “For years, we’ve sold these awards shows as women, with our gowns and colors and our beautiful faces and our glamour. This time the industry can’t expect us to go up and twirl around. That’s not what this moment is about.”

Find out more about Time's Up at timesupnow.com.