Jack Benny in Father of the Bride?
Benny so anxiously wanted the role of Stanley Banks that he consented to a screen test for producer Pandro Berman. Later, Spencer Tracy (told MGM had put the story into production with him in mind) threatened to walk off the picture after hearing about Benny's unsuccessful test. It took Katharine Hepburn's efforts as a go-between to get Tracy back on board.