John F. Kennedy Jr. and Carolyn Bessette at a New York gala in May 1999. (Mike Segar/Reuters)

Now it can be told: They lied. He was already engaged to Carolyn Bessette, whom he wed a year later in a stealth ceremony that set the standard for paparazzi-proof VIP nuptials.

Kennedy’s aide RoseMarie Terenzio — who reveals the episode in a new memoir — admits that the lie was a less-than-karmic start for her PR career. Now, she says, “I tell all my clients, ‘I will not lie for you’ . . . Those people would remember I’d lied to them and they wouldn’t talk to me again.”

RoseMarie Terenzio (Christian Lucidi)

“If you’re an actor and you don’t want to be famous anymore, you stop acting. If you’re a singer and you don’t want to be famous, you stop singing,” Terenzio told us. “John couldn’t stop being John.”

You won’t find much dirt in Terenzio’s new book about the late Kennedy scion, “Fairy Tale Interrupted.” (Cynics, don’t groan: The fairy tale was not John-John’s but hers, a working-class Bronx kid swept up in his glamorous world.) She was nuts about her boss, for whom she worked from 1994 until his 1999 death, and pals with Bessette, who treated her to lavish shopping sprees and makeovers.

Terenzio’s juiciest revelation concerns the couple’s final days. Other writers have claimed the marriage was in trouble, but Terenzio says Bessette was merely worn down by the fame and scrutiny. Irked by a lack of solo time with her husband, Bessette balked at attending a Kennedy cousin’s Hyannis wedding — until Terenzio talked her into boarding the doomed flight with him.

The book is mostly a window into the time a president’s son tried to make it in New York publishing, in the final giddy years before the Internet changed everything. (“I miss it so much, for so many reasons,” Terenzio says of the era.) She describes the paparazzi swarms, the colleagues jockeying for Kennedy’s favor, the publishers trotting him before advertisers like a prize pony — and Kennedy’s willingness, to a point, to play the game. He asked Madonna to pose on the cover in pillbox hat and suit, à la Jackie. She turned him down, Terenzio writes — though he succeeded, scandalously, in posing Drew Barrymore as Marilyn, singing her infamous “Happy Birthday” to his dad.

Hard times were on the horizon for magazines, but Terenzio believes that if her boss hadn’t died, George (which folded just over a year later) would have thrived in years to come. “With tea parties and hanging chads and Obama — oh, it was ahead of its time!”

Read earlier in the Washington Post archives: The death of John F. Kennedy Jr., July 1999