Ruah, 29, is engaged to stunt man and former Navy Seal David Olsen. The actress is due to give birth this winter.
"I'm so thrilled about having a baby boy and starting a new chapter as a parent with David," she told People.com Sunday.
"It's 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."
Notable deaths of 2014 [PHOTOS]
'True Detective' adds Kelly Reilly