DeForest Kelley was physically portrayed in the episode but had no lines due to his death in 1999.

The picture of Tesla sitting and reading underneath the Magnifying Transmitter was portrayed in the first episode.

Fall of Eagles; he is portrayed in the 3rd episode under the name "Mackenzie."

Stan Lee portrayed himself in the seventh episode, encountering Chuck "in the most unexpected of places."

Katie Couric portrayed herself in the episode.

(This incident is portrayed in the first episode of the series, truth being at least as strange as fiction).

Also, after each regeneration portrayed in the episode, music from Meglos is employed.

Robinson stated that he portrayed the character in the episode for the simple fact that he needed money for that month to pay his bills.

Harris had a guest role in the 1991 series Eerie, Indiana, portraying a central character in the seventh episode.

The show was portrayed in the final episode of Seinfeld, with Rivera as himself reporting on the lengthy trial of the show's four main characters.