Days before season five is set to premiere, AMC has granted an early but not surprising renewal to TV's No. 1 drama, The Walking Dead.

The zombie drama based on the comics created by Robert Kirkman will be back for a sixth season, though an exact episode count has not yet been revealed.

Heading into season five, The Walking Dead ranks as the top scripted series in the advertiser-coveted adults 18-49 demographic and the highest-rated show in cable history. Season four averaged a whopping 18.4 million total viewers and 12.2 million in the demo.

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"We could not be more excited for Oct. 12 as we share new episodes of The Walking Dead with fans around the globe,” AMC president Charlie Collier said. “In advance of Sunday’s season five premiere, AMC proudly confirms a sixth season order of this extraordinary series. Thank you to Robert Kirkman, Scott Gimple, the terrific executive producers, and the entire team who bring this compelling world and these rich characters to life. There’s plenty more Dead ahead thanks to their impressive, collective effort."

Walking Dead has proven such a hit for AMC that the network is teaming with Kirkman for a second series. The network in September officially ordered its Walking Dead companion series — eyed for 2015 — to pilot. Details are slim about the premise of the project, but it is expected to chronicle the early days of the zombie apocalypse, sources tell THR.

For AMC, Walking Dead's sixth season comes as the cable network is building out its original scripted programming following the conclusion of Breaking Bad and the final run of Mad Men next year. Its original programming roster includes second seasons of Halt & Catch Fire and Turn, Breaking Bad prequel Better Call Saul (already renewed for a second season), as well as martial arts drama Badlands, which was picked up straight to series and eyed for late 2015 or early 2016. Western Hell on Wheels, which hasn't yet been renewed, could join that roster.

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On the pilot side, AMC has dramas Knifeman, Galyntine and White City, as well as comedy We Hate Paul Revere, in the works. Beyond that, the network has high hopes for developing controversial comic adaptation Preacher.

In addition to both Walking Dead shows, Kirkman also has his Image comic Thief of Thieves in development at AMC with frequent collaborator Dave Alpert attached. Kirkman, who oversees Image Comics imprint Skybound as CEO, will also executive produce an adaptation of David Schulner's comic Clone for Syfy, and his exorcism comic Outcast is in the works as a pilot at Cinemax.

Email: Lesley.Goldberg@THR.com

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