"Supernatural" will soon introduce Sam's and Dean's "other grandpa," and the show runners have cast the actor to do the job.

Gil McKinney ("Friday Night Lights") will play the role of Henry Winchester, John Winchester's old man. He will first appear on the current season's 12th episode called, "As Time Goes By," HuffPost TV reported.

Spoiler alert: Due to mild spoilers given below, you are advised to read at your own risk.

How do Sam and Dean interact with their paternal grandpa? Little birdies say Sam and Dean will do some time traveling in a January episode.

Meanwhile, here is the official synopsis for the winter finale episode of Supernatural called, "Citizen Fang."

Sam asks a friend, hunter Martin Creaser, to track Benny just to be on the safe side. However, when Martin gets word of a vampire kill in Benny's neighborhood, he takes things into his own hands, forcing Dean to make a tough choice.

In a Zap2It report, Supernatural executive producer and writer Jeremy Carver has this to say about S08E09:

"[Martin's] dropped into a situation where you've got the Winchester brothers literally arguing about how they're going to essentially deal with monsters in a way that he's never heard hunters discuss monsters before. The idea of Dean having a relationship with this thing is so far from Martin's understanding. In a weird way the guy who has had [mental] issues in the past lends a bit of balance to the episode, and, frankly, an element of unpredictability as well."

Sneak Peek Video: Supernatural Season 8 Episode 9: "Citizen Fang"

Here is a video clip from "Citizen Fang." Airing Wednesday night on U.S. telly via The CW.

The series will be on hiatus for the holiday, and will return in January. You know what this means: expect yet another cliffhanger.

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