(CBR) AMC’s "The Walking Dead" heads into its fifth season with 28 million weekly viewers in tow, making it likely Rick Grimes and the other survivors will be fighting off threats both walker and human for some time to come. But for how long?

In the minds of producers, the hit drama hasn’t even reached the halfway point yet.

Indiewire reports that at the Producers Guild of America’s Produced By conference on Sunday, "The Walking Dead" Executive Producer David Alpert was asked about working from existing material — in this case, obviously, the Image Comics series created by Robert Kirkman, Tony Moore and Charlie Adlard.

“I happen to love working from source material, specifically because we have a pretty good idea of what Season 10 is gonna be,” Alpert replied. “We know where season 11 and 12 … we have benchmarks and milestones for those seasons if we’re lucky enough to get there.”

That’s undoubtedly music to the ears of AMC executives, who are already developing a companion series featuring new characters and storylines. However, even 10 seasons would be a feat for a cable drama; that would tie "The Walking Dead" with "Stargate SG-1," which split its run between Showtime and Syfy (nee Sci Fi Channel).

"The Walking Dead" returns in October for its fifth season.