Ryan Hurst (Saving Private Ryan, Remember The Titans, Sons of Anarchy, Bates Motel) has officially been cast as Beta in Season 9 of The Walking Dead.
In the comics Beta is a brutal high ranking member of The Whisperers, who initially acts as second in command to Alpha. Beta is aggressive to any and all outsiders. He is obedient to a fault and strictly adheres to the rules set by Alpha, even when she does not follow them. He is extremely protective of Alpha, partially as her bodyguard and second in command and also in part due to his feelings for her.