Broadway star Victoria Clark has been cast in a surprising and pivotal role in HomelandWarning! Major Spoiler Alert!

The Tony-winning actress will play troubled CIA agent Carrie Mathison's (Claire Danes) mother in scenes already shot in top secret, according to Entertainment Weekly.

No information was given about when Clark's scenes will air, but it is suggested that her on-screen arrival will provide a major plot development for Carrie.

James Rebhorn previously played the part of Carrie's father, Frank Mathison, for three seasons, prior to his death in March.

Homeland recently wrapped filming its fourth season, and has just been renewed for a fifth series.