Planet of the Apes (1968 film) and Linda Harrison, played Cornelius and Zira. This test footage is included on several DVD releases of the film, as well as the documentary "Behind the Planet of the Apes". Linda Harrison, at the time the girlfriend of studio chief Richard Zanuck, went on to play Nova in the 1968 film and its first sequel, and had a cameo in Tim Burton's "Planet of the Apes" more than 30 years later, which was also produced by Zanuck. Although Harrison often opined that the producers had always had her in mind for the role of Nova, they had, in fact, considered
Escape from the Planet of the Apes the second. A new character of Dr. Milo is introduced played by actor Sal Mineo, who hoped his career would gain from the new project much as McDowall's career had from participating in the first film. Charlton Heston, star of the first film and supporting actor in the second, appears in this third installment only in two brief flashback sequences. Despite "Beneath the Planet of the Apes" ending in a way that seemed to prevent the series from continuing forward, 20th Century Fox still wanted a sequel. Roddy McDowell, in the franchise documentary "Behind the Planet of the Apes", stated