During an appearance at Comic-Con, the writer and director revealed that he loved "doing something bold" with the show but did not want to detract from the comic's roots.
"I've always said I think the template left by Mr Kirkman is an extremely good one, but I've also said that we should take every interesting detour we fancy taking as long as we follow in the long term what Robert's done," he explained.
"What that's leading to is a lot of cool ideas that will surprise the hardcore fans of the comic. There's a lot of stuff happening that they're not going to see coming."
Kirkman agreed, admitting that he feared the show's storylines would be too obvious.
"That was important to me because I didn't want people watching the show and say, 'Oh, I know what's coming next'. They're doing a good job of taking the best parts of the comic, expanding them and adding new things."
The Walking Dead will debut in October on AMC.