The 46-year-old Leftovers star made no mention of the tabloid rumors going around, instead focusing on his visit to Austin Pets Alive, a shelter in Austin, Texas.
"Another very inspiring visit with the incredible people and pups [Austin Pets Alive]," the Star Wars: The Last Jedi actor wrote. "I cannot understand how they do what they do, day after day, so consistently and lovingly to save so many dogs and cats. I HIGHLY recommend going in and getting your nose bit by a toothless baby pitbull. [These] two aren't yet ready to go, but when they are go get em."
Theroux also reminded his fans in Houston that they also have a Pets Alive location as well.
Theroux included photos of himself holding two young puppies and a video of an adorable newborn puppy rolling on his back. He also posted a couple of photos of older dogs at the shelter.
Lastly, the actor also changed his bio to include just a link to Austin Pets Alive's website.
This was Theroux's first Instagram post since Feb. 8, and therefore his first post since the Feb. 15 announcement that his relationship with Aniston is over. The post also came after Theroux backed out of an appearance on The Late Show with Stephen Colbert.
The couple said the split "was mutual and lovingly made at the end of last year."
"Normally we would do this privately, but given that the gossip industry cannot resist an opportunity to speculate and invent, we wanted to convey the truth directly," continued the statement, released by Aniston's publicist Stephen Huvane. "Whatever else is printed about us that is not directly from us, is someone else's fictional narrative. Above all, we are determined to maintain the deep respect and love that we have for one another."
Ansiton and Theroux "look forward to continuing our cherished friendship."
The power couple married in 2015, though TMZ recently speculated they were never legally married because the site could not obtain proof of a marriage license.
Reports since their separation have surfaced, citing clashes over where the two would live, as Theroux liked spending time in New York, while Aniston preferred Los Angeles. Theroux's neigbor, Norman Resnicow, even told TMZ Aniston hated Theroux's apartment.
"Jen's always been nice to him and he feels sorry for her, because he believes Justin tried to force her to like his NYC pad and then bailed on her because she didn't," Resnicow said. "Everyone knows Jennifer hated the place. [Theroux] is acting crummy to her like he did to me."
Photo credit: Instagram/ Justin Theroux