Greer's first appearance as Bridget on the show will be Monday.
Kutcher joined the cast this season as a replacement for fired actor Charlie Sheen. He plays a heartbroken Internet tycoon who befriends the family of Sheen's character, the recently deceased Charlie Harper, and buys his house.
Greer is best known for her work on TV's "Arrested Development." Her film credits include "Adaptation," "The Wedding Planner," "13 Going on 30," "27 Dresses" and "Love and Other Drugs."