Although animated shorts released to theatres by Warner Brothers from the 1930s through the 1960s ransacked contemporary pop culture and show business for references, catchphrases and jokes, the upper echelon of film stars was a relatively underutilized source of graphic and vocal caricature in what came to be known as the "house style" for Looney Tunes and Merrie Melodies. Instead, Warner animation staff drew inspiration for their characters from lesser-known performers, in the process creating a number of enduring pop culture icons whose importance as signifiers in the film and entertainment worlds has not only obscured their original referents, but has also outlasted the cultural significance of much of "classic" cinema's Hollywood royalty.
Rick Cousins (Sun,) studied this question.