ET caught up with the writer and actor at Activision for the launch of the game, Call of Duty: Black Ops III, where he revealed the compliment he gives his wife, Jennifer Aniston, the most, is simply, "She's beautiful."
"Not to be corny, but it's true," he said. "So I constantly say that."
Theroux is actually an avid gamer, and told us his mancave is really just "a little office I play in and a little chair that's set up."
So, does Aniston ever join in?
"No. Jen does not play the game, and doesn't understand why I play the game, but she allows me to," he said. "She's nice enough to let me go away for a couple hours a couple times a week and play."
Well, that's what marriage is all about!
Watch Theroux gush even more about his wife below.