Despite its thorough-sounding title, “Hitchcock” is not a biopic of the Master of Suspense, but rather a lightweight behind-the-scenes account of the making of his most successful film, “Psycho,” in late 1959 and early 1960. And it’s barely even that. Distilled from Stephen Rebello’s book “Alfred Hitchcock and the Making of ‘Psycho,'” this thin, comical confection by director Sacha Gervasi (“Anvil: The Story of Anvil”) casts Anthony Hopkins as a rather buffoonish Hitch, depicted as a man obsessed with his leading ladies (true enough) and given to spying on them like a bumbling sitcom character (or, if you will, like a psychotic motel proprietor). Sigh. Fortunately, we get Helen Mirren as Alma Reville, Hitch’s wife, collaborator, caretaker, and adviser. Whether she’s affectionately nagging him about his weight or giving him shrewd tips on improving his movies, Alma is Hitch’s constant, and Mirren’s customary fire serves her well. Alma puts up with a lot from Hitch, but Mirren’s inherent dignity keeps the character from seeming like a doormat. (She has her own interests, too, pursuing a separate project with a writer friend, played by Danny Huston.) John J. McLaughlin’s humor-oriented screenplay delivers plenty of backlot Hollywood laughs, many of them hinging on the fact that we know how great “Psycho” — a dubious prospect at the time — is going to turn out. (“Is this still a picture about a queer killing people in his mother’s dress?” asks one studio exec.) Scarlett Johansson is a serviceable Janet Leigh; Jessica Biel isn’t bad as Vera Miles; and you’ll want more of James D’Arcy as the awkward, gangly Anthony Perkins. Hitch deserves a more in-depth examination than he gets here (and so does the making of “Psycho,” for that matter), but if you can disregard your desire for authenticity and scrupulous historical accuracy, “Hitchcock” is light fun with a sweet relationship at the center of it.

B- (1 hr., 38 min.; PG-13, mild innuendo and sensuality, some grisly images.)