The 48-year-old actor shared a photo of Aniston, who turned 51 on Tuesday, on his Instagram Stories along with a sweet birthday message.
The black-and-white snap shows Aniston wearing a tank top and jeans in a triumphant pose.
“… grabbing 2020 and another year just like —” Theroux wrote atop the photo. “Happy birthday B,” he added, along with a red heart emoji.
Theroux celebrated Aniston’s birthday last year, too, sharing another black-and-white photo of the Morning Show star.
“Happy Birthday to this fierce Woman,” he wrote in the caption for the shot. “Fiercely loving. Fiercely kind. ….and fiercely funny. ❤️ you B.”
While Theroux and Aniston split in February 2018 after seven years together and two and a half years of marriage, the pair have remained friends, and celebrated Friendsgiving together with several other friends last November.
“Very VERY thankful for these friends and these nights,” Theroux wrote atop the image.
Theroux has remained supportive of Aniston, too — especially after she finally joined Instagram in October.
“She has sworn she was not gonna do it, and then she did it. I’m so proud of her — I thought it was so great,” the actor told Extra after Aniston’s debut on the social media platform. “The world’s about to learn what a hilarious woman she is if they don’t already. … She’s gonna be good at this.”
“I don’t feel a void. I really don’t,” the Friends star told Elle magazine in December 2018. “My marriages, they’ve been very successful, in [my] personal opinion. And when they came to an end, it was a choice that was made because we chose to be happy, and sometimes happiness doesn’t exist within that arrangement anymore.”
“Sure, there were bumps, and not every moment felt fantastic, obviously, but at the end of it, this is our one life and I would not stay in a situation out of fear. Fear of being alone. Fear of not being able to survive. To stay in a marriage based on fear feels like you’re doing your one life a disservice.”
“When the work has been put in and it doesn’t seem that there’s an option of it working, that’s okay,” she continued. “That’s not a failure. We have these clichés around all of this that need to be reworked and retooled, you know? Because it’s very narrow-minded thinking.”
A source told PEOPLE in June 2019 that while Aniston was “genuinely happy and fulfilled by her work right now,” she’d be open to a relationship if something came along.
“She will be cautious [about dating again]. If something comes into her life, that’s fine, but she is not sitting on the edge of her seat,” the source said at the time. “It’s not because she doesn’t want to [date], but because there just hasn’t been time for her to focus on it.”
“She knows that she lives a very fun life, and she’s extremely grateful for it all,” the source added.
“When [love] comes knocking, it’s going to be welcomed. I’m not like, ‘No, I’m done with that,'” Aniston told Harper’s Bazaar last May.