"The Walking Dead" returns from hiatus to record ratings

This Jan. 28, 2013 photo shows actor David Morrissey from AMC Network's "The Walking Dead", poses for a portrait in New York. The popular zombie series returns for another eight episodes Sunday at 9 p.m. EST. (Photo by Amy Sussman/Invision/AP)
Amy Sussman

The zombies keep getting stronger.

AMC's hit "The Walking Dead" set a series record Sunday night with 12.3 million viewers. The show was returning from a hiatus, and the Nielsen Co. said it beats the series' previous record of 10.9 million for its third season debut last October.

More than half of Sunday's viewers, or 7.7 million, were in the\ youthful demographic of people ages 18 to 49. Nielsen says a cable series has never reached that big an audience in that age group.

That's impressive by broadcast standards, too. While "NCIS" on CBS was the most popular drama on the air with 22 million viewers the previous week, fewer than 5 million of those viewers were under 50.

"The Walking Dead" airs Sunday at 9 p.m. ET on AMC. The series, which will air for eight episodes this season, has won two Emmy Awards. It also received a Golden Globe nomination for best television series - drama.