AMC's companion series to "The Walking Dead" had the biggest premiere in the history of U.S. cable TV history. The 90-minute season opener of "Fear the Walking Dead" on Sunday night delivered a record-breaking 10.1 million viewers. The previous record was held by another spin-off series, "Better Call Saul," which debuted to 6.9 million viewers in February, reported the Los Angeles Times.

The new show found itself on top for both total viewers in all key demographics, which included 6.3 million viewers in the coveted 18-49 demographic, according to the Washington Post. In 2010 the flagship show "The Walking Dead" debuted to 5.4 million viewers, which was considered extremely high at the time. The zombie show's ratings got higher and higher after that. The series climbed to a record 17.3 million viewers for its fifth season premiere last fall, according to Entertainment Weekly.

"Thank you and congratulations to Robert Kirkman, Dave Erickson, the brilliant executive producers and the entire cast and crew of "Fear the Walking Dead," said AMC Presdient Charlie Collier. "It is increasingly difficult to evaluate a show's success on night one. However, we are releasing these live/same day ratings because Fear the Walking Dead delivered record-breaking numbers that are all the more special in this era of time-shifted viewing and audience fragmentation. To have a companion series to the #1 show on television driving communal, urgent viewing, social activity and pop cultural relevance of this magnitude is truly differentiating. Of course none of it is possible without the fans, whose passion leads to these remarkable results."

"Fear the Walking Dead" airs on AMC Sundays at 9 p.m. EDT.