Colfer has been cast as Tony, the son of actress Victoria Chase, who is played on the acclaimed series by Wendie Malick.
The young actor is scheduled to film his episode next week.
The TV Land comedy also stars Betty White, Valerie Bertinelli and Jane Leeves.
In addition to his acting credits, Colfer wrote the screenplay for the 2012 indie film "Struck By Lightning," which he also produced and starred in, and the "Land of Stories" children's book series.