Switched at Birth follows Bay (Vanessa Marano) and Daphne (Katie Leclerc), teenagers from different walks of life who have learned they're living with the wrong family. Bay, who comes from a privileged background, is really the daughter of single mother Regina (Constance Marie) while Daphne, who is hearing-impaired, is actually the child of Kathryn(Lea Thompson) and John (D.W. Moffett).
Marini, who recently played Luc on ABC's Brothers & Sisters, begins shooting his episode next week. It will air as the season finale on Monday, Aug. 8.
Switched at Birth debuted earlier this month as ABC Family's most-watched series premiere ever with 3.3 million viewers.