JFK & Princess Grace: Their Secret Love Affair That Could Have Changed History

Princess bride Grace Kelly nearly became America’s first lady — as Mrs. John F. Kennedy — if JFK had his way.

Five years before he married Jacqueline Bouvier, the future president carried on a blazing affair with Kelly, then a fledgling Hollywood movie star.

“I fell in love the moment I saw her,” Kennedy told another one of his many lovers, Swedish aristocrat Gunilla von Post, who later went on to talked about the affair.

“JFK always tried to conceal his red-hot romance with Grace,” noted a historian who has covered both Hollywood and the White House. “But it became an open secret and that infuriated Jackie to no end.”

In her memoir, “Love, Jack,” Gunilla revealed that JFK told her that he’d flipped for only one other woman in his life — Grace Kelly.

“I simply fell for her,” JFK confessed.

The stunning romance was also recounted in the book “True Grace: The Life and Times of an American Princess,” by Wendy Leigh.

“There is no documentary proof of what happened between Grace and Jack or why their relationship never evolved into anything long-lasting,” Leigh wrote.

But the author noted that a clue may be found in the work of historian Priscilla Johnson McMillan, who believed JFK’s power-mad dad, Joseph P. Kennedy Sr., nixed the budding romance.

“Joe wanted Jack to marry Grace, but then Joe decided that she was too Hollywood,” said McMillan.

After her fling with JFK, the beauty went on to win the Best Actress Academy Award for the 1954 drama “The Country Girl.”

Both JFK and Grace had very influential fathers. Grace’s dad was John Kelly, a three-time Olympic gold medalist and successful multimillionaire from his bricklaying company. JFK’s dad was influential in politics and also wealthy from his real estate company and bootlegging.

Joe had had a well-known affair with a Hollywood star himself — actress Gloria Swanson. In fact, they once had a rendezvous on his yacht, and 12-year-old JFK was there at the time. He was so embarrassed that he jumped off the boat and tried to swim to shore.

The fathers had known each other and secretly planned for their kids to wed so they could combine their business interests. But Grace and JFK had different interests. Grace became an actress while Jack was interested in politics — something Grace thought was low class and somewhat dirty. She aimed higher. So after their brief fling, she was the one who ended it, and shortly afterward found her destiny with Prince Rainier III of Monaco.

When Grace married Rainier in 1956, author Gore Vidal — whose stepfather later married Jackie’s mother — revealed JFK couldn’t stop gazing at photos of the star-studded nuptials.

“Jack studied the pictures intently, then frowned and said: ‘I could have married her,’” recalled the late author, adding that Jackie was furious.

Before Grace died in 1982 at age 52, she revealed she’d paid a visit to the president-to-be while he was laid up in the hospital — at Jackie’s urging.

Grace recalled, “I had been to a dinner party where I had met Mrs. Kennedy and her sister [Lee Bouvier] for the first time. They asked me to go to the hospital with them to pay a visit to help cheer him up.

“They wanted me to go into his room and say I was the new night nurse!”

At first, Grace was reluctant.

“Well, I hesitated,” she said. “I was terribly embarrassed. Eventually, I was sort of pushed into the room by the two girls.”

Jackie’s social secretary, Letitia “Tish” Baldrige, later admitted, “Grace had a relationship with the president before his marriage to Jackie, and Jackie knew about it.”

Baldrige said Jackie even cut short a formal White House event honoring Grace and Prince Rainier.

Originally scheduled as a four-hour, black-tie dinner, Jackie insisted that the occasion be changed to an 80-minute luncheon.

And Grace’s behavior fanned the flames of the first lady’s jealousy.

“Grace was like a schoolgirl with Jack,” recalled Baldrige. “It was hero worship. An old boyfriend who was now president of the United States — why shouldn’t she be overwhelmed?”

After JFK’s assassination in 1963, Grace said in an interview, “I believe that God allows these certain tragedies to happen in order to emphasize the man and his achievements and to inspire those who follow to have the strength and the will to accomplish his unfulfilled dreams.”

Grace also reflected on what attracted her to JFK. “His youth,” she said. “He was one of my own generation, so that for the first time in my life I became deeply involved, spiritually and sympathetically, with the presidency — the office as well as the man.”

“I felt personally involved.”

But Jackie made sure she was always first in her husband’s heart, no matter how many flings or lovers he played footsie with over the years. They exchanged vows on Sept. 12, 1953, and Jackie quickly realized that JFK would never stay true to her, says a friend.

“Even while they were on their honeymoon in Acapulco, JFK flirted with almost every attractive woman who crossed his path,” the source says.

Said Jackie: “Jack was the love of my life. No one will ever know how big a part of me died with him in 1963. I never stopped loving him.”