Even the Grammy Awards can’t slow the momentum of AMC’s “The Walking Dead,” which resumed its third season Sunday with more record ratings.

Already the most popular ad-supported cable series in history, “The Walking Dead” averaging a whopping 12.3 million viewers in its regular 9 p.m. timeslot, according to Nielsen. This tops the previous high for a single telecast of the drama, 10.9 million for last fall’s third-season premiere.

Sunday’s premiere also drew a combined 4.3 million viewers for its repeats at 11 p.m., midnight and 2 a.m., bringing its total viewership for the night to 16.6 million.

Compared to the second-half launch of its sophomore season at this time a year ago, Sunday’s episode was up by 45% in adults 18-49 (7.7 million vs. 4.3 million) and by 52% in total viewers (12.3 million vs. 8.1 million). The year-ago winter premiere also went up against the Grammys, with last year’s kudocast drawing an audience of nearly 40 million (vs. 28.4 million last night).

AMC ordered 16 episodes of “The Walking Dead” this season, with the first eight airing in the fall and the current eight wrapping the show’s third season on March 31.

In the fall, “Dead” stood as TV’s top-rated drama among adults 18-49, even besting broadcast biggies like “Grey’s Anatomy,” “NCIS” and “Revolution.”

Sunday’s preliminary 18-49 rating of 6.1 bests all drama telecasts this season as well as the 6.0 for the season premiere of Fox’s “American Idol.” In fact, among all episodes of entertainment series this season, only the Jan. 10 episode of CBS’ “The Big Bang Theory” (6.4 rating in 18-49) drew more young adults than Sunday’s “Dead.”

Following “The Walking Dead” on AMC, the premiere of a new episode of post-show series “Talking Dead” drew 4.1 million viewers, including 2.7 million adults 18-49 (a 2.1 national rating). The show, hosted by Chris Hardwick, has been expanded to an hour for the second half of this season.