“Halston used to have me over for dinner,” the 70-year-old Vogue veteran writes, “and he would serve a baked potato with caviar and sour cream. For dessert: a small mountain of high-class cocaine served in an Elsa Peretti sterling silver bowl.”

Added Talley, “I snorted a line or two, to be polite to my host, and that was it. I never wanted to feel out of my sphere of control. My destiny was not to be hooked on coke.”

Born Roy Halston Frowick, the late American couturier often hosted over-the-top, debaucherous soirées for the likes of Andy Warhol, Liza Minnelli, Bianca Jagger and Diane von Furstenberg at his NYC “party pad.”

But Halston’s love of drugs was hardly unusual in the era of Studio 54, Talley writes: “The new wave of designers were working, loving and living on a regular diet of cocaine, then the drug du jour … Halston thrived on it. He was known to partake and afterward stay up and change a whole collection overnight. Presto: a masterpiece.”

Out Wednesday, Talley’s book was bumped up from its initial September release date thanks to breathless media coverage of the memoir’s more scandalous passages about the author’s former boss, Anna Wintour.

In “The Chiffon Trenches” — which, interestingly, Talley has called a “love letter” to the iconic editrix — the Condé Nast vet describes Wintour as “ruthless” and “not capable” of “human kindness.”