“The Girl” 9 p.m. Saturday, HBO

“There’s only so much I can teach you through kindness,” the director Alfred Hitchcock tells actress Tippi Hedren in the new movie “The Girl,” which premieres Saturday on HBO. But the astonishing cruelty that Hitchcock inflicted on Hedren had little to do with teaching, and much to say about his own obsessions. And “The Girl” offers a portrait of a great artist as petty monster.

Hedren starred in two of Hitchcock’s films, “The Birds” (1963) and “Marnie” (1964). While something of a novice as an actress, in looks the model recalled several of Hitchcock’s blonde, beautiful leading ladies, among them Grace Kelly, Eva Marie Saint and Kim Novak.

He made some actresses very uncomfortable with various sorts of advances and lewd comments, which Hitchcock biographer Donald Spoto says would immediately be seen as sexual harassment today. But Spoto found the director’s relationship with Hedren to be especially painful and complicated, with Hitchcock constantly pursuing Hedren even after she repeatedly spurned the aging, married director.

The hardcover edition of Spoto’s book “Spellbound by Beauty: Alfred Hitchcock and His Leading Ladies” has an awkwardly posed Hitchcock and Hedren on the cover. And in that book, which is the basis for “The Girl,” Spoto argues that no Hitchcock film after “Marnie” “has any emotional statement to make.” As much as he tried to punish Hedren, Hitchcock may also have destroyed himself.

Written by Gwyneth Hughes and directed by Julian Jarrold, “The Girl” stars Toby Jones as Hitchcock and Sienna Miller as Hedren and traces their relationship from Hitchcock’s discovering Hedren in a TV commercial through the completion of Marnie.

At first, Hitchcock appears to be a charming mentor schooling Hedren in the film arts. But he also aims to dominate and mold her, decreeing that a string of pearls she wears is wrong, or choosing her lipstick color, then ordering a new wardrobe to match the lipstick.

He becomes increasingly determined to possess her sexually, reciting dirty limericks, and making an awkward and semi-public pass at her. When Hedren resists, he asserts his power, notably in a scene in “The Birds” where Hedren is attacked by live birds over days of shooting, after she had been assured the scene would use mechanical birds and take less time.

While Miller is good, it is at moments like the bird-attack scene when it is clear how much the movie is taken over by Jones. His face blends the need to dominate with an often powerful sense of shame — shame not only at what he is inflicting on Hedren, but shame over a desire he cannot control any more than he can control the actress.

Believing he has created her, he is all the more frustrated by her independence, as this unsettling, tension-laden movie makes so clear.