Gene Wilder was the original choice for Corky, and director Richard Attenborough and writer William Goldman wanted him, but producer Joseph E. Levine refused, on the grounds he wanted no comedians in the movie to distract from the serious nature of the story.
William Goldman, in his book "Five Screenplays" (1997) said of the film: "Burgess Meredith was perfect, and Tony Hopkins (Anthony Hopkins) was so wonderful here. But running stride for stride with him was Miss Olsson. I think Ann-Margret is the least appreciated emotional actress anywhere."
To prepare for his performance in this movie, Anthony Hopkins learned magic tricks and studied the art of ventriloquism. Hopkins learned how to project his voice and manipulate a ventriloquist's dummy.
Upon seeing Fats for the first time, Anthony Hopkins was allowed to take the doll home to work with it. However, he wound up being so unnerved by it that he called the consulting ventriloquist in the middle of the night, threatening to throw Fats into the canyon if someone didn't come and get the doll immediately. Director Richard Attenborough ended up going to Hopkins' house to calm him down.
Gene Siskel ranked the movie at the number nine spot on his Ten Best Films of the Year list for 1978.