On May 19, 1962, at a fundraiser and early birthday celebration for President John F. Kennedy, Marilyn Monroe shimmied onto the Madison Square Garden stage, shrugged off her glamorous fur coat to reveal a skin-tight, rhinestone-encrusted gown, and stepped up to the microphone.

"Happy Birthday, Mr. President," she famously crooned in her signature sultry, yet strangely childlike voice. "Happy Birthday to you."

youtubeView full post on Youtube

If the public did not already believe that the Hollywood sex symbol and the commander-in-chief were secret lovers, Monroe's sexy performance would make them the subjects of intense speculation for decades to come and lead to relentless tabloid reports filled with lies and doctored photos of the two of them together —especially since Monroe would die just months later.

Photograph, Photography, Portrait, Smile, Event, White-collar worker, Suit, Formal wear, pinterest
Hank Walker/The LIFE Picture Collection/Getty Images, Alfred Eisenstaedt/Pix Inc./The LIFE Picture Collection/Getty Images/

It was certainly something salacious to imagine; they were two of the most famous (and most attractive) figures in the world at the time, and rumors of the president's extramarital affairs were widely disseminated. But when it came to the alleged Monroe-Kennedy romance, how much truth was there behind all the gossip? Not much, according to multiple sources, including historian Donald Spoto, author of the 1993 book Marilyn Monroe: The Biography.

According to most accounts, there are only a few times throughout their lives that Kennedy and Monroe could have encountered one another.

Arthur Miller and Marilyn Monroe, April in Paris Ballpinterest
Al Pucci/NY Daily News Archive via Getty Images
Arthur Miller and Marilyn Monroe at the April in Paris Ball, 1957

In April 1957, both Monroe and Kennedy reportedly attended the April in Paris Ball at the Waldorf-Astoria Hotel in New York City, but did not meet. After all, they were with their respective spouses (Monroe with playwright Arthur Miller, and Kennedy—then the senator of Massachusetts—with Jacqueline), and there were over 1,000 people in attendance.

Four years later, in 1961, the actress and the newly elected President of the United States were rumored to have both been at a dinner party hosted at the Santa Monica home of actor Peter Lawford. Lawford's wife, JFK's sister Patricia Kennedy Lawford, happened to be a close friend of Monroe's. However, while JFK did attend a luncheon at Lawford's on the day in question, it can't be confirmed that Monroe was also in attendance, Buzzfeed reports.

The most plausible night for an affair would have been March 24, 1962, multiple historians agree. Both Monroe and Kennedy are thought to have been at Bing Crosby's Palm Springs, California, home for a party. In Marilyn Monroe: The Biography, biographer Donald Spoto quotes Marilyn's close friend and masseur Ralph Roberts, who claims that while on the phone with Monroe that weekend, he heard what sounded like Kennedy's voice. Monroe had called to ask for professional massage advice—Kennedy famously had a bad back—and Kennedy apparently even took the phone to talk to Roberts himself.

"Marilyn told me that this night in March was the only time of her 'affair' with JFK," Roberts said. "A great many people thought, after that weekend, that there was more to it. But Marilyn gave me the impression that it was not a major event for either of them: it happened once, that weekend, and that was that."

Actress Susan Strasberg, daughter of Lee Strasberg and close friend of Monroe, corroborated this story in her unpublished memoir. "It was O.K. to sleep with a charismatic president," Susan said, "and Marilyn loved the secrecy and the drama of it, but Kennedy was not the kind of man she wanted to spend her life with, and she made that very clear."

If they were indeed together a Bing Crosby's home on the date in question, it's possible that Kennedy asked Monroe to sing at his birthday that very night. At the time of the celebration, Monroe was filming Something's Got to Give and had been struggling with sinusitis and her dependency on barbiturates, both of which delayed the movie schedule, reports Karina Longworth in an episode of the podcast You Must Remember This.

Black, Black-and-white, Music, Musician, Performance, Monochrome, Monochrome photography, Photography, Performing arts, Musical instrument, pinterest
Yale Joel/Life Magazine/The LIFE Picture Collection/Getty Images

She was well enough to fly to New York to fulfill her commitment to the president, but the studio used this pre-planned absence as an excuse to cancel the film while blaming Monroe and suing her for a breach of contract. In reality, it wasn't all Monroe's fault (and she had requested the time off to attend the gala in advance). The movie was already falling behind because the script kept getting rewritten.

The fundraiser birthday party was the last known night when Kennedy and Monroe may have crossed paths. After singing the supposedly scandalous version of "Happy Birthday," Monroe transitioned into a rendition of "Thanks for the Memory" with lyrics she penned for the man of the hour.

Pianist, Musician, Standing, Piano, Technology, Electronic device, Electronic instrument, Black-and-white, Photography, Keyboard, pinterest
Bettmann/Getty Images
"Thanks, Mr. President / For all the things you've done / The battles that you've won / The way you deal with U.S. Steel / And our problems by the ton / We thank you so much."

When JFK took the stage to thank her, he said, "I can now retire from politics after having had Happy Birthday sung to me in such a sweet, wholesome way."

Following the event, White House photographer Cecil Stoughton snapped the only existing photo of the two figures—at a crowded after party held at movie executive Arthur Krim's house.

Photograph, White, Black, Monochrome, Black-and-white, Monochrome photography, Snapshot, Standing, Photography, Film noir, pinterest
Cecil Stoughton/The LIFE Images Collection/Getty Images

Interestingly, before she went on stage earlier that night, the star was introduced as "the late Marilyn Monroe"—a crack at her frequent tardiness to film sets. But in hindsight, the title can be seen as a sad form of foreshadowing. Less than three months later, on August 5, 1962, Marilyn would be found dead of a barbiturate overdose in her Los Angeles home. She was 36. Although conspiracy theories persist, some involving the Kennedy family and an alleged coverup, her death is widely accepted as either suicide or accidental.

One year later, on November 22, 1963, President Kennedy was assassinated in Dallas, Texas. He was 46. And as for their alleged affair? If anything, it was more of a one-night-stand, by most accounts.

(h/t: PopSugar)

Headshot of Taysha Murtaugh
Taysha Murtaugh
Lifestyle Editor

Taysha Murtaugh was the Lifestyle Editor at CountryLiving.com.