Justin Theroux and Jennifer Aniston reunite to mourn death of dog Dolly

Jennifer Aniston and her ex-husband Justin Theroux appeared to reunite for a heartbreaking farewell of their dog Dolly — who tragically died over the weekend.

Theroux penned a letter to their dog on Instagram after holding a memorial service for their beloved pooch.

The 47-year-old captioned the post: "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 one that never deserts, the one that never proves ungrateful… is the dog — faithful and true, even in death," the star continued, quoting late US Senator George Graham Vest. "Rest in Peace Dolly. #adoptdontshop #rescuedog."

The couple who announced their split in 2017 — seemingly put their past behind them and got together to grieve their late white shepherd hybrid.

Theroux posted a series of images that paid tribute to his dog, with Dolly wrapped in a blanket and sprinkled with flower petals.

The Maniac star appeared to be holding Aniston's hand in the ceremony, though this has not been confirmed.

Many friends of the former couple commented on the post to send their best wishes.

"We love you Dolly," Courteney Cox, Aniston's former Friends co-star, commented.

"RIP beauty," Orlando Bloom wrote.

"Awwww I'm so sorry Justin," Amy Sedaris said.

Aniston and Theroux split up in February after being married for two-and-a-half years. Following their breakup, they agreed to shared custody of the dogs.

The Friends star looked after Dolly, a terrier named Clyde and their pit bull mix named Sophie in her LA mansion. Theroux kept their other pit bull in his New York home.