Chris Pratt felt like a "stereotypical soldier" shooting Zero Dark Thirty overseas, because he desperately missed his wife Anna Faris and stared at a photo of the pregnant actress.

The actor headed to the Middle East to film the thriller on location while Faris was expecting their first child, and he admits being apart from her made the experience all the more real.

He tells, "Anna was really pregnant and I didn't take it lightly that we would be travelling in the Middle East.

"It was this funny thing where I felt like one of the stereotypical soldiers you see in movies, you know, where he is always staring at a picture of his pregnant wife back home."

But Pratt insists the couple's top priority was keeping in touch. He adds, "She ended up working in England so on a couple of weekends I was able to travel to London and see her there, which was really great. With (video chat services) Skype and FaceTime, it was a lot easier than I expected it to be."

The stars' baby boy Jack was born last August (12), and the actor admits he is loving his new role as a dad.

He says, "(Fatherhood) is a real return on your investment. You have to invest more as the kid gets older. You can't just set them down in the crib and walk away. They are going to run around and require more of your attention and more nurturing. But with that comes their ability to say, 'Daddy, I love you,' which will happen one day. Well, at least I hope he says that."