A favorite film has long been 1944's Double Indemnity, directed by Billy Wilder, and starring Barbara Stanwyck, Fred MacMurray, and Edward G. Robinson.
The movie's script was written by Mr. Wilder and the novelist Raymond Chandler, and was based on the novel of the same name by James M. Cain.
I've seen Double Indemnity a number of times, yet never knew, until just recently, that Raymond Chandler appears in the film.
Mr. Chandler is seen in the movie for only a few seconds. He is seated outside the office of Barton Keyes, the insurance investigator played by Mr. Robinson. Walter Neff (Mr. MacMurray) sells policies for the same insurance agency, and leaves Keyes's office. Mr. Chandler is in a chair, holding a cigarette and reading a book, or perhaps a magazine. He looks up as Walter Neff passes by.
Here is the scene, from YouTube:
