According to The Hollywood Reporter, in other cable pilot castings, Brandon Routh, Hal Linden, Amir Arison, Tina Majorino and Kevin Michael Richardson have joined TBS' In Security, and Garcelle Beauvais, Reed Diamond and Dana Davis have boarded Franklin and Bash, another hourlong TBS pilot.
Also at TBS, Tim Jo and Josh Brener have been added to the 1980s fraternity comedy pilot Glory Daze.
Walking Dead, based on Robert Kirkman's comic book, chronicles the months and years following a zombie apocalypse and revolves around survivors, led by police officer Rick Grimes, who travel in search of a secure home.
Bernthal will play Grimes' partner and friend Shane, an outgoing bachelor.
In Security revolves around two sisters (Constance Zimmer and Kat Foster) who take over their father's (Linden) private-security business protecting the super-elite while dealing with personal and family issues.
Routh will play a former Navy SEAL-turned-bodyguard at the firm who sleeps with one of the sisters.
Richardson, Majorino and Arison also will play employees of the company.
Franklin and Bash revolves around Jared Franklin (Breckin Meyer) and Steven Bash (Mark-Paul Gosselaar), two street lawyers and lifelong friends who, after taking down a white-shoe law firm in a high-profile case, are recruited by the firm's patriarch, Stanton Infeld (Malcolm McDowell).
Diamond will play Infeld's nephew; Beauvais-Nilon will play the nephew's girlfriend.
Davis will play an employee at the firm.