Daniel Day-Lewis as Abraham Lincoln. Denzel Washington as Malcolm X. Meryl Streep as Margaret Thatcher. So many historical figures instantly evoke famous faces who’ve played them on the big screen. But where’s our Harriet Tubman? For one of our country’s most badass historical icons, she’s been soundly snubbed by Hollywood.

We’re on the brink of putting her on money, and she hasn’t had a movie to her name yet?

Cynthia Erivo’s towering performance in “Harriet” finally changes all that: As the woman who escaped slavery in Maryland only to risk her life countless times going back to rescue fellow slaves, this British star of Broadway and the London stage brings a gravity to the role that all but guarantees Oscar will come calling.

It’s a shame, then, that the movie, which had its world premiere last night, doesn’t measure up to its star (who was breathtaking in a frothy, apricot-hued Christian Siriano dress with a long train). Though deeply well-intentioned, director Kasi Lemmons’ movie never really breaks free of conventional biopic mode or demonstrates any particular stylistic flair in her telling of the pivotal events of Tubman’s life.

We meet Tubman when she’s a slave called Minty, trying to get her owners to accept a lawyer’s letter stating that if she and her free husband have children, the young ones will be free as well. (Spoiler alert: This doesn’t go over well.) Tubman finally gets up the courage to run, though she’s forced to leave her husband behind as she flees.

William Still (Leslie Odom Jr., the original Aaron Burr of “Hamilton”) is waiting for her in Philadelphia; he’s the founder of an abolitionist center welcoming escaped slaves into free Pennsylvania, and a member of the Underground Railroad. But it’s not long before Harriet — her chosen free name — is heading back into slave territory again, vowing to bring more people with her when she returns, even against Still’s admonitions that it’s too dangerous to do alone.

Janelle Monáe is luminous as the owner of a boardinghouse that caters to recently escaped slaves, and a new friend to Harriet, but she can’t do much with the leaden dialogue.

“Harriet” picks up speed as its heroine does, making trips back and forth with terrified slaves and navigating the inherent peril in evading both trackers and the potentially fatal dangers of the woods at night. Henry Hunter Hall is a highlight as a tracker named Walter, initially enlisted by white men to catch the “slave stealer” who’d become known as Moses — but changed by seeing Tubman’s fierce spirit and her close relationship to God (she regularly had visions she attributed to divine guidance). By the time Tubman’s leading a Union Army raid to free slaves during the Civil War, you’ll likely be thrilled in spite of the film’s shortcomings. Her final confrontation with her repellent owner Gideon (Joe Alwyn), one of the few over-the-top dramatizations, gives the kind of catharsis you expect from a Hollywoodized version of Tubman’s story — and that’s OK.

Lemmons doesn’t sugarcoat the story, but “Harriet” is a far cry from the brutal realism of films like “12 Years a Slave.” Although apparently not yet rated, it reads to me as PG-13, which means kids can watch it. Which is great! The simplicity with which this story is told makes it an ideal watch for a younger audience just learning about Tubman and America’s history of slavery, only beginning to be taught in schools without whitewashing. What better entry point for learning about one of America’s real-life superheroes than this bravura performance from Erivo?