the walking deadAMC screencap"The Walking Dead" is one of the highest cable ratings winners on AMC.

"The Walking Dead" is currently one of the most successful cable shows on television.

Based on the comic series of the same name by Robert Kirkman, the show follows a group of survivors living in a zombie-filled apocalypse.

Now in its third season, the show is viewed by tens of millions and shows no signs of slowing its growth. 

Every time "The Walking Dead" returns from a hiatus or starts a new season, it shatters its own ratings record. When the series returned from its winter break in February, it had a record 12.3 million viewers 

What is it about the zombie series that makes it must-watch TV?

Sure, it's full of immensely life-like detailed zombies, action-packed, nail-biting moments, and, after this season, we know no character is ever safe from getting axed, but the success of the series is due to more than just that.

Business Insider spoke with "The Walking Dead" producer David Alpert to find out what it is about the show that gets tens of millions of people viewing Sunday nights.

"People tune in for the characters," adds Alpert. "They are emotionally invested in these people, the dilemmas, and moral choices. I think if we did this today as just a straight zombie action show I don't think anybody would watch. Or, there would be a very small audience; just the hardcore fans. And, that's not what we do."

Alpert tells Business Insider that fans tell them they watch the show for the character relationships.

"We have so many people come and tell us, 'I don't watch horror, and I don't watch zombie stuff, but I watch your show, I read your books, because I love Rick, I love Tyrese, I love Lori, and I have to know what's happening to my favorite characters."

arrow cwCW With the success of an adapted comic book series in "The Walking Dead," more networks are turning to the format for inspiration.

Since its debut on AMC in 2010, others have tried to capitalize on the show's success in film and television.

CW has had success with turning comic series "Arrow" into a television series this past fall.

Later this year, we'll see even more shows become reliant on book and comic adaptations.

ABC hopes "S.H.I.E.L.D.," based on Marvel's secret intelligence agency, will follow in the success of last year's "The Avengers." NBC is betting on "Wonderland" based on Lewis Carroll's popular fairytale series. 

Lionsgate and Summit recently released a spin on the zombie genre with romantic comedy "Warm Bodies" about a boy slowly becoming human again after being turned into the walking dead. The film has grossed $98.9 million in theaters worldwide. 

Later this summer, Brad Pitt will star in the anticipated book adaptation of zombie film, "World War Z." 

"People have reacted to zombies," says Alpert. "But I feel that the people who are trying to imitate that aspect only are missing the broader lesson from 'The Walking Dead.'"

"We've taken this crazy idea that the dead have come back to life, but we've grounded it so much that these characters seem real," says Alpert. "So you believe in their stakes. And, people get emotional about it. And, the reason I think the show is so successful is because they care so much. Afterward, people debate — 'What would I do in the same situation?'"

Of course, this isn't the only thing that makes the zombie show such a massive hit. 

Alpert also credits much of its success to the show's connection with its massive fan base.

Like other shows, "The Walking Dead" and AMC teams have live tweets coming from multiple accounts during the show including @WalkingDead_AMC and @TheWalkingDead. However, AMC takes it one step further. 

After every airing of "The Walking Dead," it's followed by a live recap and discussion called "The Talking Dead."

Hosted by Chris Hardwick, the show has became so popular, it's now an hour long and has been moved up an hour to directly follow the first showing of "The Walking Dead." (It used to be that "The Walking Dead" aired twice, back-to-back, followed by a half-hour episode of "The Talking Dead.")

"If we did this today as just a straight zombie-action show, I don't think anybody would watch." – David Alpert, producer, "The Walking Dead"

To bring together all their fans in one place, Skybound Entertainment recently launched, a one-stop shop to encompass the show, the comic book series, the novels, and the various video game titles with message boards and forums for the fans. 

"Historically, you'd have to spend millions of dollars in market research, and we have this direct engagement with the fans," says Alpert. "When we do something and they don't like it, we know it instantly … and, we also know when they love something with real-time feedback [during live shows]."

Alpert adds, "We really believe we have the best fans in the world — they're passionate, they're boisterous, and they're vocal, but we wouldn't have it any other way. "