The term bombshell is a forerunner to the sex symbol and originally used to describe popular female sex icons.
Bombshells are a special kind of sex symbol. Whereas nearly any notable entertainer can qualify as a sex symbol, bombshells are popular icons who became legends after they die. They are "entertainers with a sensational effect.".
Stephanie Smith, Household Words: Bloomers, sucker, bombshell, scab, nigger, cyber (2006) on changing usage of the word.
Theda Bara (1910s) Josephine Baker (1920s - 1930s) Clara Bow (1920s) Joan Crawford (1920s - 1930s) Greta Garbo (1920s - 1930s) Gloria Swanson (1920s) Marlene Dietrich (1930s - 1940s) Jean Harlow (1930s) Made film titled Bombshell in 1933 Ann Sheridan (1930s - 1940s) Mae West (1930s) Betty Grable (1940s) Rita Hayworth (1940s) Carole Landis (1940s) Veronica Lake (1940s) Hedy Lamarr (1940s) Dorothy Lamour (1940s) Carmen Miranda (1940s) Gene Tierney (1940s) Lana Turner (1940s - 1950s) Diana Dors (1950s) Audrey Hepburn (1950s - 1960s) Jayne Mansfield (1950s - 1960s) Marilyn Monroe (1950s - 1960s).