Veteran actor Edward G. Robinson was recruited to play the role of Dr. Zaius in the March 1966 Planet of the Apes screen-test. The screen-test was to persuade Twentieth Century-Fox executives of the viability of a movie about talking Apes. While the makeup (initially created by Ben Nye, not to be confused with the design by John Chambers for the actual film) was under scrutiny, the promised involvement of such Hollywood big-hitters as Edward G. Robinson and Charlton Heston was also used as leverage to green-light the project. It should be remembered though, that as the main actor demonstrating the ape makeup, the performance given by Robinson was what, more than anything else, cleared the way for the movie to finally go ahead. The screen test showing Robinson as Dr. Zaius can be seen on the 1998 documentary, Behind the Planet of the Apes, and has since been added as bonus material on DVD releases.
Robinson was committed to the role and looked forward to working with Heston. Ultimately, however, he found the experience of working under such heavy makeup very uncomfortable and restrictive, and he reluctantly pulled out of the project around April 1967, weeks before filming began. Both Charlton Heston and Kim Hunter maintained that a recent heart-attack was the reason that Robinson could not agree to wear the oppressive ape make-up for a three-month filming schedule.
Robinson,who had earlier co-starred in The Ten Commandments, would go on to star with Heston again in another of Heston's three sci-fi classics, Soylent Green. This would prove to be Robinson's final movie, as he was terminally ill during filming and died a matter of weeks after the film was completed.