As the upcoming season of 'The Walking Dead' nears its premiere date, the hit AMC series continues to expand its cast as Xander Berkeley recently signed on for a role that is yet to be disclosed.

The 59-year-old actor, widely known for his role as George Mason on Fox's political thriller ‘24,’ is set to be featured in the sixth season of the hit zombie drama in a recurring role.

Although sources have already confirmed to TVLine that Berkeley's character will not be the comic book villain Negan, it has also been revealed that the unknown character does have similar qualities with the series’ greatest antagonist.

Referred to as a narcissist, Berkeley’s character has “a huge ego and prioritizes self-preservation above anything else.”

Moreover, TVLine stated that the actor’s new role is set to enjoy his superiority and control above the rest but remains charming and pleasant to many.

Last month, The Spoiling Dead Fans shared the actual casting call for the new character, stating: "Narcissistic, egotistical, quick to braggadocio and anger, his own skin is his principal concern. He feeds off the superiority of being in control, but he plays it off with Senator-like charm. He's vibrant, and has the charisma of a car salesman."

Although details about the new character are being kept under wraps, fans who have read through the source material are speculating that Berkeley is playing the comic book character Gregory.

He makes his debut in the comics as the arrogant and vainglorious self-absorbed leader of Hilltop Colony. Members of the farming community, which is 20 miles from the Alexandria Safe-Zone, had been mindful of Gregory's faint-hearted nature. Nonetheless, they also believed him to be the most capable leader they had.

On the other hand, Gregory thought better of himself; instead of a coward, he claimed that his decisions have been meant for the benefit of the town instead of his own well-being.

The character is also known for his playful nature around women. He had even flirted with Maggie during some time in the comics.

Berkeley is set to join ‘The Walking Dead’ during the second half of season six; viewers will then be only able to see him early next year. The actor’s deal also states that he could be promoted to a series regular in the seventh season.

‘The Walking Dead’ season six is set to premiere with a special 90-minute episode on Oct. 11 on AMC.