Claire Danes and Hugh Dancy are expecting their third child.
The couple already has two sons, Cyrus and Rowan.
The news of the pregnancy comes ahead of the Golden Globe Awards, where Danes is nominated for Best Supporting Actress in a Limited Series.
It is unclear when Danes are due.
Danes has previously spoken about the challenges of motherhood.
Danes worked until she was in her eighth month of pregnancy with her first son.
Danes's oldest son, Cyrus, has spent time on the set of Homeland.
Danes has said that being a mom can be challenging and that there is pressure to talk about motherhood in romantic terms.
Danes has also talked about feeling physically responsible for her children and pregnancy's chemical changes.