The character of Irene Denore, as played by the late Nina Foch, is inspired by Greta Garbo. Like Garbo, she is a reclusive movie star from the Golden Age who requested to be alone.
Bill Bixby, who had creative control over the show, brought many Golden Age of Hollywood actors to guest star in The Magician (1973) This episode guest-stars veteran actors Nina Foch and Ian Wolfe who both co-starred in different films with the Master of Horror, Bela Lugosi. Foch portrayed a disciple of Armand Tesla, his vampire character in The Return of the Vampire (1943), and Wolfe appeared opposite Lugosi in The Raven (1935). Later Bixby would pay tribute to Bela Lugosi by dedicating The Last of the Red Hot Vampires (1987) to Lugosi, whom he named by his birth moniker, as "Mr. Blasko".
Not the first time - nor the last - that the "angels" would draw inspiration from this series, the premise of a recluse Golden Age of Hollywood movie star being extorted or otherwise harassed - and "gaslighted" - would, 3 years later, be the theme for I Will Be Remembered (1977), guest-starring Ida Lupino.
The work-in title was "Night of the Serpent".
Along with the many other changes to the series that started with this episode the title of this show and all the ones that follow begin with "The Illusion of."