The comedy drama - which was formerly known as both Good Christian Bitches and Good Christian Belles - is produced by Sex and the City's Darren Star.
Alejandro will appear in one episode as Danny, a local butcher who is romantically interested in Heather (Marisol Nichols), according to Entertainment Weekly.
The actor plays Jesus Velasquez on True Blood and previously starred in NBC / TNT cop drama Southland.
Bowler will play another love interest, with his character Mason Massey becoming attracted to Cricket (Miriam Shor).
He starred as Cooter in the third season of True Blood and has also appeared in episodes of Lost and Ugly Betty.
Last month, Days of Our Lives actor Eric Winter signed up for a recurring role on GCB.
The series will debut on ABC in early 2012.
> Tom Everett Scott joins Good Christian Belles
Watch the trailer for GCB below: