The couple - who divorced in 2017 after two years of marriage and six years of dating - celebrated the Thanksgiving holiday together among some of their famous friends, including Courteney Cox, Jimmy Kimmel and Jason Bateman.
As RadarOnline.com previously reported, the former Friends actress hosted the dinner at her Bel Air home and teased Kimmel - who suggested she have Mexican food for her party- with her serving of enchilada.
But her reunion with Theroux will shock fans. The two were captured in a selfie the actor posted on his Instagram page.
In the group shot of the Thanksgiving party's attendees, the Friends star is spotted holding on to Theroux's shoulder as they smiled into the camera.
As readers know, Aniston, 50, and Theroux, 48, have remained good friends following their breakup.
The Charlie's Angels actor joked he was one of the first people to follow the actress when she recently started her account on Instagram.
“The world is about to discover how hilarious she can be,” Theroux added.
Back in July, the Leftovers actor reunited with Aniston to mourn the death of their beloved dog, Dolly, with an intimate memorial.
In an Instagram post, Theroux posted heartbreaking photos from the service, one of which included a photo of him holding hands with Aniston as they laid the German Shepherd to rest.
Aniston rescued Dolly in 2006 from a shelter, but Theroux quickly took on the role of the pup’s daddy.
“Tonight, at sunset, after a heroic struggle… our most loyal family member and protector, Dolly A. laid down her sword and shield. She was surrounded by her entire family,” the star wrote. “The one that never deserts, the one that never proves ungrateful… is the dog— faithful and true, even in death.”
“Happy Birthday to this fierce Woman. Fiercely loving. Fiercely kind. ….and fiercely funny. Love You B,” Theroux wrote in his Instagram page with a photo of Aniston in black and white at the time.
Theroux also went to Aniston's 50th birthday bash where her other ex-husband, Brad Pitt, was also in attendance.
Despite remaining friendly, Aniston and Theroux have both moved on romantically. Theroux was spotted making out with model Brooks Nader, while Aniston claimed she is “very, very busy” & “hates” being set up on dates.
However, their Thanksgiving reconciliation shows the stars can't quit each other completely and will likely always be important in each other's lives.