Village People will see Garth playing a career woman who adopts a baby, Deadline reports.
Garth's character ends up taking care of both the baby and the child's biological mother, who is a teenager.
Garth is probably best known for her role as Kelly Taylor in Beverly Hills, 90210 and the CW reboot 90210.
Sadie Calvano, who recently worked on Fox's pilot Family Album, has also joined Village People as the baby's mother.
My Generation's Sebastian Sozzi will play one of Alexa's friends, as will Rachel Cannon, who has previously appeared in shows such as Ghost Whisperer and Two and a Half Men.
Other projects currently in the works at ABC Family include a drama about college students who solve crimes and a Sutton Foster show called Bunheads.