David Gerrold was the author of the novelization of Battle for the Planet of the Apes. He was the writer of several science fiction novels and scripts, including the Star Trek book 'The Trouble With Tribbles', published in February 1973. At around the same time Award Books, having secured the book rights to the Apes movies, were looking for someone to write a novelization of the fifth movie, adapting the shooting script so that the book could be released simultaneously with the movie. Award asked advice from Judy-Lynn Del Rey, editor of 'Galaxy Magazine' (who shared the same building), who suggested Gerrold. He requested a cameo role in the then-unfinished movie as part of the deal, through which he could write a publicity piece for a magazine.
Gerrold spent two days in February 1973 on set at the Fox Ranch, where they were filming the climactic ape/mutant battle scenes. Serving as an ape extra, he was too tall to play anything other than a chimpanzee, and wore the 'Roddy-Double' design, of the six standard chimp appliances available. His on-screen action was limited to 'stunt' work in the background of the battle, later recalling, "I wasn't in any close-ups. I ended up being a dead body in one shot."
Two months later (April 20th-22nd) the first 'Star Trek West Coast Convention' was held, as part of Equicon '73 at the Los Angeles International Hotel. David Gerrold featured as the emcee for the event's masquerade, and carried out his duties disguised as Cornelius, after a public make-up demonstration by Apes crew-member Werner Keppler.
- David Gerrold Interview - 'Simian Scrolls' #5 (at Hunter's Planet of the Apes Archive)