In a heartfelt Instagram post, he shared a black and white photo of Jen holding up a viking helmet.
"Happy Birthday to this fierce Woman," he wrote.
"Fiercely loving. Fiercely kind. ....and fiercely funny. ❤️ you B."
Last year, in a new interview with The New York Times, the actor, 47, broke his silence about their divorce — revealing that the two went their separate ways without any hostility.
“The good news is that was probably the most — I’m choosing my words really carefully — it was kind of the most gentle separation, in that there was no animosity,” he explained.
“Again, neither one of us is dead, neither one of us is looking to throw hatchets at each other,” he added. “It’s more like, it’s amicable. It’s boring, but, you know, we respected each other enough that it was as painless as it could be.”
That doesn’t mean there wasn’t sadness for Theroux and Aniston, 49.
“It was heartbreaking, only in the sense that the friendship would not be the same, as far as just the day to day,” Theroux said. “But the friendship is shifting and changing, you know, so that part is something that we’re both very proud of.”