"He makes a surprising appearance," Mazzara told The Wrap. "I don't want to give anything away as to the exact episode, but the audience will certainly be ready for his appearance - and they won't have to wait too long."
The showrunner added that Morrissey's take on the Governor will be "very complex, nuanced" and "multi-layered".
"This will not be simply an arch villain who is committing an evil act in every scene," he explained. "That's too cartoonish for what we do here. We want that character to feel as real and human and fully developed as possible."