 Their relationship during the development of the film was also dramatized in the 2013 Disney film "Saving Mr. Banks".In March 1961, Disney announced that it might cast Hayley Mills and Mary Martin in the film.Julie Andrews, who was making her feature film acting debut after a successful stage career, got the prime role of Mary Poppins soon after she was passed over by Jack L. Warner and replaced with Audrey Hepburn for the role of Eliza Doolittle in his screen adaptation of "My Fair Lady" even though Andrews had originated that role on Broadway.