Gregory Allen Howard spent more than two decades trying to get his screenplay about famed abolitionist Harriet Tubman into theaters. He wanted to portray Tubman — a black woman who escaped slavery and then helped dozens of others do the same — as an action hero, not just as the protagonist of a history lesson.

So even after “Harriet" was released this month, with Cynthia Erivo in the lead role, Howard could not shake the memory of his first big Hollywood meeting over the project in 1994.

“This script is fantastic. Let’s get Julia Roberts to play Harriet Tubman,” an executive told him, in an exchange the screenwriter recounted to Focus Features earlier this month.

As the conversation went on at an unnamed Hollywood studio, the lone African American producer in the room spoke up, reminding the others that Tubman was black.

“That was so long ago,” the executive answered. “No one is going to know the difference."

Those eyebrow-raising comments sparked an outpouring of anger and ridicule Tuesday night, rapidly making Roberts-as-Tubman the latest — and possibly most absurd — example of Hollywood’s whitewashed casting choices.

“White people: please meet the dagger that drives into our hopes and dreams on a daily basis,” said Rebecca Carroll, a black cultural critic and the editor of special projects at WNYC.

Howard did not publicly reveal the name of the studio or the executive. His publicist did not immediately respond to The Washington Post’s requests for additional detail on the incident late on Tuesday.

But that didn’t keep the Internet from sharing its outrage over the idea of a white Tubman, played by an actress whose heritage traces back to Northern Europe.

Jordan Crucchiola, an associate editor at the entertainment news site Vulture, suggested that “a jar of cockroaches” was more qualified than the executive who proposed casting Roberts.

“If you’re chasing a Hollywood dream and feel doubtful you’ll ever make it, remember there are executives getting paid [expletive] loads of money to suggest JULIA ROBERTS should play Harriet Tubman,” Crucchiola wrote.

Howard, who also penned the scripts for “Remember the Titans” and “Ali,” pointed to the instance as an example of the obstacles he faced trying to sell a script about an African American heroine to an industry dominated by white men.

First titled “Freedom Fire,” his movie follows Tubman as she escapes from slavery on the Eastern Shore of Maryland, leads others to do the same on the Underground Railroad and emerges as a major voice for abolition and suffrage.

“The number of doors slammed in my face, the number of passes, the number of unreturned phone calls, canceled meetings, abandonments, racist rejections, the number of producing partners who bailed, are too many to list,” Howard wrote.

It wasn’t until recent years, when black-led movies like “12 Years a Slave” and “Black Panther” smashed box-office records, and campaigns like #OscarsSoWhite pushed for greater racial representation, that Howard was able to see “Harriet” through to theaters.

“What I realize now is that the film was not going to get made until the environment in Hollywood changed,” he wrote in the Los Angeles Times. “Hollywood had to go through its own climate change.”

For many on social media, however, the executive’s comment served as a reminder of some much more recent examples of how movie studios have cast — or thought about casting — white actors to play people of color.

First and foremost in comparisons on Twitter was Scarlett Johansson, who has waded through a number of such controversies: After taking on the lead role in a 2017 adaptation of the Japanese anime “Ghost in the Shell,” and almost playing a transgender man in a forthcoming feature, she asserted in July that she “should be allowed to play any person.”

“Hollywood is wild, man. People of color, friends in the industry, stay sane and grounded as you deal with this madness. Laugh at the absurdity if possible,” said Wajahat Ali, a playwright and contributing op-ed writer for the New York Times, mentioning Johansson by name in a tweet.

Johansson was just one of several actors mentioned as an example of Hollywood’s racially questionable casting decisions: from Angelina Jolie’s turn as a mixed-race woman with Afro-Cuban heritage, to Emma Stone starring as a half-Asian pilot, and Johnny Depp depicting a member of the Comanche Nation. (Depp has said he has some Native American heritage.)

On social media, some used the occasion to point out what they saw as a double standard: In the rare instances when people of color were cast in roles perceived as white, backlash has followed. (For instance, angry fans charged that African American singer Halle Bailey should not star as Ariel in the live-action version of “The Little Mermaid.”)

Others were bewildered about how the same actress who played the white, blond-haired Erin Brokovich could also convincingly portray a dark-skinned Tubman in a movie depicting slavery.

“So … wait … was the exec expecting Julia Roberts to go full-on Blackface like Birth of a Nation,” tweeted comedian W. Kamau Bell, “OR just completely ignore the source material like Emma Stone in Aloha?”

If there’s one thing that separated this latest casting controversy, however, it’s that the actress at its center had seemingly nothing to do with stirring it up.

Besides trending on Twitter overnight, Roberts — without doing anything at all — managed to revive a year-old Internet meme involving rapper Nicki Minaj, who had compared herself to Tubman, and prompt some to wonder about Tubman starring in her own films.

As of early Wednesday, Roberts had yet to comment on the matter.