Mr. and Mrs. Ellsworth are played by the real life husband and wife Gavin MacLeod and Patti MacLeod.
Roddy McDowell previously played Professor Arthur Chapman in the episode The Man Who Made Volcanoes (1977).
This is the second appearance of Ed Begley, Jr. as Harold Farnum, he first appeared as this character in Season 2 "Diana's Disappearing Act" (1978).
Diana Prince doesn't transform, on-screen, into Wonder Woman.
Frank Gorshin, Caroline Jones and Roddy McDowall all appeared on Batman and Wonder Woman. Frank Gorshin played the Riddler and the Deadly Toymaker, Roddy McDowall played the Bookworm and Henry Roberts, and Caroline Jones played Marsha and Hypolitta.