Hidden Figures” began as an underdog tale. It turned into a hit movie. Now it seems on the verge of becoming a social movement touchstone. Inspired by its message of empowerment for African Americans and women, boosters have offered up multiple free screenings  of the film.

The story about three African-American women who pushed back against racism and sexism to help advance America’s space program has proven so inspirational that it is expected to push past the $100 million domestic box office barrier this weekend.

Word of mouth appears to be the powerful driver of most the film’s box office. But the movie also got a little lift from its stars, director and from producer/musical creator Pharrell Williams and, more recently, from outside groups that are offering free seats to “Hidden Figures” at several locations around the world. Some of the screenings are open to all, while others have been arranged to benefit girls, women and the underprivileged.

The campaign began as an individual bit of activism by one of the films stars, Octavia Spencer, and has now made a total of more than 1,500 seats for “Hidden Figures” available, free of charge, to poor individuals and families.

Spencer paid to have the film shown at the Baldwin Hills theater in Los Angeles leading into the Martin Luther King Day holiday weekend. “If you know a family in need that would like to see our movie but can’t afford it have them come,” she wrote on Instagram. “It’s first come, first served.”

Around the time of that screening, Spencer and her “Hidden Figures” co-star Janelle Monae were at an event for L.A.’s Promise — the non-profit that supports local schools. Monae learned from Spencer about her donating one screening to the poor. Monae liked the sound of that and decided to sponsor an audience of underprivileged viewers, as well, according to someone familiar with the campaign.

That news, in turn, got to “Hidden Figures” director Ted Melfi, who got others involved in the effort to expand the audience for the film. Stars Taraji P. Henson and Jim Parsons signed on, along with Melfi himself and producer-musician Williams, who has been one of the most tireless supporters of the film.

The end result was seven more screenings for people who otherwise might not have been able to afford to see the 20th Century Fox film — in Atlanta (sponsored by Monae), in Washington DC (sponsored by Henson), in Chicago (also Henson), in Houston (by Parsons), in Hazelwood, Missouri (by Melfi and actress/co-producer Kimberly Quinn), in Norfolk and Virginia Beach, Virginia (both sponsored by Williams.)

All of the screenings went off at 2 p.m. last Sunday. “This movie means so much to me,” Williams wrote on Twitter, “I want to share it with you.”

A 20th Century Fox spokesperson said the studio helped with logistics but the cast and crew members worked directly with the theaters to arrange the showings. They then blasted out social media messages, to make sure people got out to see the film.

And, though the free screenings began with the “Hidden Figures” crew, they appeared to have a long shelf life. On Friday evening, Chaffey College in San Bernardino County announced via Twitter that it was holding a free screening of the film. Arizona State University’s Barrett Honor’s College slated a free showing for Feb. 1. A Decatur, Georgia non-profit, the Stewart Foundation, announced it would be sponsoring its gratis showing for young people on February 4.

And those were just the showings readily apparent via social media. they do not includes several other local efforts by groups and individuals to use crowd-funding sites on the Internet to raise money to bring even more people to the movie.

And the volunteer exhibitions were not limited to the U.S. The Australian Mathematical Sciences Institute announced it was joining with a foundation to offer tickets to multiple screenings of the film at three locations in March. Their “ChooseMaths” program, an online posting says, is designed to “to turn around community attitude to participation in mathematics, especially for girls and young women.”