James Cromwell can be seen watching from the side in one of the shots, and he is one of the two guys that lifts up Fred Astaire at the end of the song "Sluefoot".
"Chaplin, Keaton, Gilligan. The great ones make it look so easy." - ALF
15 year old James Cromwell went to Hollywood to film one movie. Then he returned home, finished high school, went to college, and didn't act professionally again for almost 20 years. Sounds plausible.
shareHave you read the Trivia section?
"Despite being listed on IMDb as an uncredited extra in this film, well known actor James Cromwell explained on the 11 July 2013 episode of the Opie and Anthony Show radio program that it was a different actor with his same name that appeared in this film."
Now, who's right?