Spoilers for "The Walking Dead" comics lie ahead!

If Glenn Rhee (Steven Yeun) isn't dead yet, he better start watching his back (or, more realistically, the back of his skull) -- as AMC's "The Walking Dead" has finally found its biggest bad yet.

AMC confirmed to MTV News that Jeffrey Dean Morgan of "Supernatural" and "Grey's Anatomy" fame has been cast in the role of Negan, the charismatic leader of a group called The Saviors who subjugate the Alexandrians in exchange for their protection against groups like The Wolves. THR reports that Timothy Olyphant, Matt Dillon and Garret Dillahunt were also considered for Negan, who will first appear as a recurring character, then join as a full-timer in Season 7.

Rumors of Negan's arrival have been circulating for years, but the recent casting of Tom Payne as Jesus -- who will show up in Alexandria any day now -- kicked things into hyperdrive, as Jesus is a crucial figure in the Alexandrians' war against Negan and his Saviors.

Production on the Season 6 finale begins in Atlanta this week.