Marilyn Monroe was an American actress, model, and singer who became a major sex symbol in the 1950s and 1960s. She starred in several films, including Gentlemen Prefer Blondes and Some Like It Hot, and is remembered for her iconic performance of 'Happy Birthday, Mr. President' for John F. Kennedy in 1962. Monroe's personal life was often tumultuous, and she died at the age of 36 from an overdose of barbiturates.