The ABC Family project focuses on Emma (Alexandra Chando), a foster child who discovers that she has an identical twin called Sutton.
Sutton was adopted by wealthy parents and appears to have a perfect life, but ends up going missing.
Deadline says that Buckley has joined the cast as Sutton's adoptive father. The character is described as "happily married" and works as a plastic surgeon.
Buckley previously starred as David Wallace in The Office and recently appeared in Life As We Know It and The Other Guys.