Teacher's Pet pits education against experience..... and Doris Day against Clark Gable. It's the star power more than the conceit of the story that draws you into this film, partly because it just seems like such an unlikely pairing.  Though both stars were big names, Clark Gable was nearly twenty year's older than Day. Cary Grant and James Stewart both turned down the role, citing the age difference between themselves and Day as the reason. Gable, older than either, took the role instead. To help accommodate their male lead, several changes were made to the film. Instead of a mere reporter, Gable's character Jim became the newspaper editor. Other changes happened too; in fact, myth has it that the movie was deliberately filmed in black & white in an attempt to disguise Gable's age and weight. The tactic doesn't entirely work. Gable is not the debonair man that made ladies swoon in Gone with the Wind.   He is heavier. He is aged. And yet, they turn that to his advantage, giving him a grizzly persona that is nonetheless very rugged and manly, and the script lampshades the topic by pointing out how boring a perfect man is. Perfect he may not be, but Clark Gable is still Clark Gable at any age.  Doris Day herself recalled, "I could actually feel the magnetic force of his personality. He dressed in marvelous tweeds. There was something very affirmative about him, and a directness that suggested great inner strength. He projected utter simplicity. A man who lived on the simple, down-to-earth scale. Very much like James Cagney.”