Just in time for Sunday’s Women’s Equality Day, dozens of Hollywood stars and organizations signed an open letter calling for equal pay among women in film and television production. 

The letter, published by the group Reel Equity, cites a recent study by Working IDEAL, commissioned by the union IATSE Local 871, which found that workers in historically female fields in the entertainment industry — such as script supervisors, production coordinators, and art department coordinators — “are paid hundreds or even thousands of dollars per week less than counterparts in comparable male-dominated crafts.”

Additionally, more than half of the women responding to the survey said they had witnessed or experienced sexual harassment over the past three years, with 13 percent saying it happened “often.” As Reel Equity’s letter explains, this “shines a light on the deep connection between the gender pay gap and other forms of workplace injustice facing women in Hollywood and beyond.”

The letter also mentions the California Pay Act of 2016, which prohibits employers from paying women less than men for “substantially similar work.” Nevertheless, the aforementioned gap still exists.