“I’m so thrilled about having a baby boy and starting a new chapter as a parent with David,” the 29-year-old actress told People on Monday.
“Its amazing how in love I am with this little person I’ve only seen on a black and white screen. I’m starting my own family and there is no other feeling like it," she added.
Ruah, whose parents are Portuguese citizens, met Olsen on the set of her hit CBS show. Her fiance, 37-year-old David, is a former Navy SEAL and a stunt double for "NCIS: Los Angeles" star Eric Christian Olsen.