Callaway Went Thataway (1951)

Two smart marketing people, Mike Frye (Fred MacMurray) and Deborah Patterson (Dorothy McGuire), resurrect some old movies starring cowboy "Smoky" Callaway (Howard Keel) and put them on television. The movies are a big hit and the star is in demand. Unfortunately, no one can find him. When lookalike "Stretch" Barnes (also Howard Keel) sends in a photo, the marketing team hires him to impersonate Callaway. Things get sticky when the real Callaway eventually shows up.