Kourtney Kardashian’s Instagram is going to look and sound different on Wednesday. Same for Julia Roberts’, Ashley Graham’s, Gwyneth Paltrow’s, Hilary Swank’s and many more.

Those white stars and dozens more will hand over their accounts to nearly four dozen black women in an attempt to amplify the latter’s voices beyond their usual social media reach.

Among the pairings: Black Lives Matter co-founder Opal Tometi will take over model Graham’s account, InStyle editor at large Kahlana Barfield Brown will take over actress Roberts’ account, WME Chief Marketing Officer Bozoma Saint John will take over reality star Kardashian’s account, author Latham Thomas will take over actress Paltrow’s account and Angelica Ross will take over actress Swank’s account.

“When the world listens to women, it listens to white women,” the campaign said in its mission statement. “For far too long, Black women’s voices have gone unheard, even though they’ve been using their voices loudly for centuries to enact change. Today, more than ever, it is NECESSARY that we create a unifying action to center Black women’s lives, stories, and calls to action.”

Self-identified “disruptors” Saint John, Luvvie Ajayi Jones, Glennon Doyle and Stacey Bendet Eisner pulled together the campaign, which has an estimated reach of 300 million Instagram users. The goal is to magnify the voices of black women and shed a brighter light on the work they’re doing in order to catalyze change.

The black women participating come from the ranks of executive business leaders, activists, journalists, educators and more. They include executive Kimberly Blackwell, #MeToo creator Tarana Burke, broadcaster Cari Champion and CSULA professor Melina Abdullah, for starters.

Other famous white participants include actress Ashley Judd, journalist Katie Couric, actress Mandy Moore and soccer star Megan Rapinoe, to name a few.

The hashtag is #ShareTheMicNow.