The actors, 38 and 57, respectively, confirmed the news through their rep Wednesday via People.
"We are so excited and feel so unbelievably lucky to have this little person coming to us!" they told the mag.
The couple, who married in 2008, are already parents to daughter, Vesper Vivienne, 3. Vesper is said to excited to meet "MY baby," the mag reported.
The "Big Love" alum, who has been nominated for an Emmy and Golden Globe Award, is expecting her newest addition this summer.
Ruck, who appeared in the late '90s sitcom "Spin City" and classic comedy "Ferris Bueller's Day Off," has two children from a previous marriage: Emma, 26, and Sam, 19.
In November, it was announced that "The Killing," which was canceled twice by AMC, will be resurrected for a six-episode fourth season on
It is unclear how or if Enos' pregnancy will affect production of the beleaguered crime drama.
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