Aldridge, Monroe, & Miller At 'April In Paris Ball'

Marilyn Monroe, Belle of the Ball

Forgotten and classic photos of the actress — and JFK — at the yearly "April in Paris" in New York.

Among the most high-profile events of the 1950s social season in New York was the annual "April in Paris Ball" — held at the posh Waldorf Astoria in midtown Manhattan. The brainchild of the hotel's banquet manager, Claude Philippe, the inaugural fete in 1952 commemorated the 2,000th birthday of the city of Paris. It soon became an annual tradition, luring socialites and celebrities alike, while raising funds for American and French charities. In hindsight, the 1957 gathering was something of a watershed year for the event, as both Marilyn Monroe and then-Senator John F. Kennedy were in attendance. Take a peek at forgotten and classic photos from the event. (Pictured: Financier and former diplomat Winthrop Aldrich seated beside Marilyn Monroe and playwright husband Arthur Miller.)

A Royal Engagement New York Post Archives/The New York Post via Getty Images A Royal Engagement The Duke and Duchess of Windsor (center) were the night's guests of honor. (After his abdication in 1936 and time as governor of the Bahamas during World War II, Edward and wife Wallis Simpson settled into a sort of retirement, frequently jetting between their home base in Paris and New York City.) They're seen here with socialite Mary McBurney Gaynor and French ambassador Herve Alphand. Mrs. Arthur Miller Peter Stackpole Mrs. Arthur Miller Following the success of 1955's "The Seven-Year Itch," Monroe took a hiatus from Hollywood to focus on her relationship with husband Arthur Miller, whom she married in 1956. At the time, rumors circulated that event planner Elsa Maxwell had invited Monroe (who made a fashionably late entrance) to embarrass the Duchess. A Prelude to Camelot Bettmann/Bettmann Archive A Prelude to Camelot In 1957, JFK was just a junior senator from Massachusetts — it would be more than three years before he successfully ran for the presidency. He's seen here with wife Jacqueline and sister Eunice Kennedy Shriver. The April in Paris Ball is also believed to be the first time Monroe and JFK were documented at the same place at the same time. I'll Never Tell Peter Stackpole I'll Never Tell Aldrich, a prominent banker and brother-in-law to John D. Rockefeller Jr., had just finished his ambassadorship to the U.K. in February of 1957. One can only speculate as to what secrets Monroe was whispering in his ear... Model Citizen Slim Aarons/Getty Images Model Citizen The Kennedys were frequent attendees at the annual ball. In fact, back in 1954, a 24-year-old Jackie had walked the runway modeling a French design as part of the festivities. A Regal Ringmaster Slim Aarons/Getty Images A Regal Ringmaster The April in Paris Ball continued to draw bold-faced names throughout the '50s, including a tuxedoed Marlene Dietrich, who performed two songs at the circus-themed 1959 event — the last one to be held at the Waldorf Astoria.