Corey Stoll, Laila Robins Corey Stoll, Laila Robins

In Treatment's Laila Robins and House of Cards' Corey Stoll have joined the cast of Homeland for Season 4, Showtime announced Tuesday.

Robins will play Martha Boyd, a new series regular who is the United States Ambassador to the Islamic Republic of Pakistan. Stoll will guest-star as Sandy Bachman, the CIA Chief of Station in Pakistan and a rising star in the Agency.

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The fourth season is slated to begin production later this month in Cape Town, South Africa.

Homeland will return this fall on Showtime.

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(Full disclosure: is owned by CBS, Showtime's parent company.)