Also appearing in All About Eve is the ditsy movie star from Hollywood Miss Casswell (Marilyn Monroe), introduced by Addison De Witt (George Sanders) as "a graduate of the Copacabana school of dramatic art." This is but one of the hundreds of unforgettable lines penned by writer/director Joseph L. Mankiewicz...
Davis was a character, an icon with grand style, so even her excesses are realistic.
The Great Movies 2002, Roger Ebert, P. 28.
And in All About Eve she was excessive and so very realistic.