Paul Archuleta/FilmMagic

There’s a new little guy on the set of NCIS: Los Angeles!

Daniela Ruah and fiancé David Olsen welcomed their first child, son River Isaac Ruah Olsen, on Monday, Dec. 30, the actress confirms to PEOPLE exclusively.

“He’s healthy and strong, which is all we could ask for,” Ruah, 30, tells PEOPLE. “We are so happy, so thankful and feel so blessed to have brought him into the world.”

Ruah and Olsen met on NCIS: Los Angeles, where she plays Special Agent Kensi Blye. Her fiancé, a former Navy SEAL, acts as a stunt double for his younger brother Eric Christian Olsen on the CBS drama.

The couple had announced the pregnancy in September.

“I’m so thrilled about this new chapter as a parent with David,” she told PEOPLE at the time.

“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.”

— Sarah Michaud with reporting by Patrick Gomez

Non condivido le tue idee, ma darei la vita per vederti sperculeggiare quando le esporrai.