AMC's The Walking Dead is putting four key members of its cast on lockdown.

The zombie drama has promoted Jeffrey Dean Morgan, Tom Payne, Austin Amelio and Xander Berkeley to series regular, The Hollywood Reporter has learned.

The quartet boarded the drama based on Robert Kirkman's comic series in season seven as recurring, with Morgan making his debut as famed villain Negan in the finale. All four play key characters from the comic books. Payne is hero Jesus, currently supporting Rick (Andrew Lincoln) and his band of survivors. Amelio is Dwight, a badly burned member of Negan's dastardly Saviors who has a particular bone to pick with Daryl (Norman Reedus). And Berkeley is Gregory, the shady leader of the Hilltop Colony who is poised to clash with Maggie (Lauren Cohan) — provided the pregnant Alexandria Safe Zone resident survives the finale.

The promotions come as little surprise as most Walking Dead stars begin their time with the series as recurring with options to be promoted to regular. Katelyn Nacon (Carl's love interest Enid), meanwhile, is still considered recurring.

The four additions to the full-time cast bring The Walking Dead's roster to 20 series regulars (up two from season six), an all-time high for the drama overseen by showrunner Scott M. Gimple. The series parted ways with (as in killed off) characters portrayed by series regulars Tovah Feldshuh (Deanna) and Alexandra Breckenridge (Jessie). The series also killed off recurring characters Denise (Merritt Wever) and Nicholas (Michael Traynor) last season.

Here's the full list of series regulars for season seven: Lincoln, Reedus, Steven Yeun (Glenn), Cohan, Chandler Riggs (Carl), Danai Gurira (Michonne), Melissa McBride (Carol), Michael Cudlitz (Abraham), Lennie James (Morgan), Sonequa Martin-Green (Sasha), Alanna Masterson (Tara), Christian Serratos (Rosita), Josh McDermitt (Eugene), Seth Gilliam (Father Gabriel), Ross Marquand (Aaron), Austin Nichols (Spencer), Morgan, Payne, Amelio and Berkeley.

The cast ranks will likely lose at least one regular when the finale cliffhanger is resolved and Negan's victim is revealed to be one of the 11 staples left kneeling before the ruthless killer. Meanwhile, the casting for comic book character Ezekiel is expected to be revealed soon as the series prepares to introduce yet another community, The Kingdom, and likely take on the source material's "All Out War" arc in a battle against Negan and the Saviors.

Morgan (Watchmen, The Good Wife) is repped by UTA and Bloom Hergott; Payne (Luck) is with Paradigm, Untitled and Felker Toczek; Amelio (Everybody Wants Some) is with UTA and Brillstein; and Berkeley is with Paradigm, Affirmative and Stone Genow.

The Walking Dead returns in October. A premiere date and trailer will be announced this month at San Diego Comic-Con. Stay tuned to THR.com/WalkingDead for complete coverage.