The recent BBC series The Serpent prompted a surge of interest in 1970s fashion, as viewers thrilled to the lapels, flares and big sunglasses of Jenna Coleman in the role of Charles Sobhraj’s spellbound accomplice. You can be the witless moll of a serial killer and still look chic, as American fashion designer Halston would surely agree.

Eerie resemblance is not what Ewan McGregor pulls off in this mini-series, though there is a frisson when the designer hits on his own look in the bathroom mirror: bronzer, black turtleneck, slicked-back hair and shades. McGregor evokes Halston with a droll yet imperious voice, a leopard-like prowl and a cigarette always held at a precise angle. Halston finds fame when he’s name-checked during the Kennedy inauguration as the designer of Jackie’s pillbox hat. As the 1960s progress, a fresher spirit begins to blow along the boulevards; hats are out and gowns are in. His first collection is a dud: “I was brilliant — they’re the dummies.” Then, shrewdly: “I’m too big for that room.”

Halston realises it’s all about the setting: white walls, clean lines, his favourite blooms, detail, detail, detail. He just needs a “teensy, weensy million dollars” to pull it off. “Orchids are part of my process — you can’t put a budget on inspiration!” How to deliver exclusivity at scale is the conundrum: “If everybody can have something, what’s the point of having it?” he protests to major backer David Mahoney (Bill Pullman), who wants to get Halston in bed with Max Factor for a perfume line. On the personal side, promoting his favourite bossy rent-boy to boyfriend is a less considered move, even if his street name is Victor Huge-o.

Gian Franco Rodriguez is mesmerising, if somewhat repellent, as the highly strung Victor, with Sullivan Jones dignified in defeat as outgoing lover Ed, palmed off with a job at the shop. Rory Culkin is sharply amusing as the window-dresser plucked from obscurity and dispatched thence almost as quickly, though not before introducing his mentor to tie-dying. Rebecca Dayan is swanlike as sidekick Elsa Peretti and Krysta Rodriguez puts in a high-powered yet tender performance as Liza Minnelli, even if, as Halston notes, one rendition of “Liza with a Z” is more than enough.

McGregor’s own performance could be seen as a riposte, even a rebuke, to Daniel Day-Lewis’s prissy turn in Phantom Thread. They are very different beasts. For one thing, unlike those of the preposterous fictional fashion designer Reynolds Woodcock, Halston’s clothes are sublime, as he drapes, folds and wraps his way around the liberated female form. What’s the betting that “tie-dye kaftan” becomes the next top internet search?

★★★★★

On Netflix now

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