Fifty years past his heyday, and 30 years after his death, the world still knows Alfred Hitchcock by reputation, even if you can’t get the kids to check out his classic movies. “Hitchcock,” a dark and dazzling bio-thriller about the making of “Psycho,” could change that.

It’s a fanciful film buff’s delight, a grim yet glittery corner of Hollywood history given a “Hollywood” treatment. No, it’s not the literal truth, but as they’ve said since John Ford’s day, “When the legend becomes fact, print the legend.”

We catch Hitch (Anthony Hopkins) as he’s at the very height of his fame — just after the dazzling success of “North by Northwest,” on a roll with “Vertigo” and “Rear Window” just behind it. He’s on TV, introducing his weekly mystery-horror-thriller series “Alfred Hitchcock Presents.” He’s being offered everything from the first-ever James Bond film to “The Diary of Anne Frank.”

And what does he want to do to top that? Shock movie audiences to their very marrow. He wants to prove that he’s not the true “relic” his wife, Alma (Helen Mirren), and others joke that he is as he turns 60. A man with phobias and fetishes to fill a book is obsessed with the story about “the boy who dug up his own mother.” He has an assistant (Toni Collette) buy up every copy of Robert Bloch’s novel, “Psycho,” to keep the public from knowing the story. And he immerses himself in the life and crimes of Ed Gein, the Wisconsin farmer whose gruesome crimes in the 1940s and ’50s inspired everything from “Psycho” and “The Texas Chainsaw Massacre” to “The Silence of the Lambs.”

“What if,” Hitch ponders, in that slow British drawl, “someone really good made a horror picture?”

Hopkins’ gift for mimicry is put to brilliant use as he inhabits the “corpulent” form of Hitchcock — uptight yet playful, with a mordant, morbid sense of humor that he was never shy about trying out on friends, new acquaintances and the general public. An actor not new to impersonating historical figures, this ranks with Hopkins’ very best work in that field.

Gein gets under his skin, and director Sacha Gervasi (“Anvil!”) and writer John J. McLaughln (“Black Swan”) imagine Hitch imagining Gein’s life and crimes. Gein, played with creepy skill by Michael Wincott, starts visiting Hitchcock’s dreams.

That doesn’t help the old director’s marriage. Alma, much in demand as a story editor, is being courted by a charming hack writer (Danny Huston, smarmy to perfection) who may have more than getting his latest book into better shape and into her husband’s hands on his mind.

The fact that studios are balking at the very idea of filming something this grotesque means that Hitch finances it himself, that he feels added pressure because of that. And the delight of coming on set each day to torment his curvaceous leading lady, Janet Leigh (Scarlett Johansson, on the money), and insult his former fave Vera Miles (Jessica Biel), isn’t enough to settle his nerves.

An inventive film, “Hitchcock” doesn’t neatly line up with “real” history, but that doesn’t spoil it in the least.