"We are so excited and feel so unbelievably lucky to have this little person coming to us!" Enos, 38, and Ruck, 57, told People.com in joint statement Wednesday.
The child's gender and anticipated birth date were not disclosed.
The "World War Z" actress and "Spin City" actor have a 3-year-old daughter named Vesper Vivienne.
Notable deaths of 2014 [PHOTOS]