Merton of the Movies (1947) on Netflix

Merton Gill is an usher from Tinkerton, Kansas, who yearns to be a movie actor and thinks his worthless diploma from the Budolph School of Dramatic Acting will help him realize his dream. When Merton foils a robbery - supposedly using the skills he learned from his idol, Lawrence Rupert - the fading film star's gun-toting lackeys bring Merton to Hollywood to drum up some much-needed publicity. But after a speedy photo shoot, Rupert and his underlings are through with the country bumpkin and give him a ticket back home. A resolute Merton remains in Hollywood and does his best to get a job at Mammoth Studio, where he befriends the famous Beulah Baxter's stunt double, Phyllis Montague. Merton proves to be a natural - if unintentional - comedian and gets a job burlesquing Lawrence Rupert. Only Merton thinks he is playing a serious part.