We have some sad news to pass along for animal lovers and Fuller House fans alike, as the Fuller family dog Cosmo has passed away. According to a tweet from the Fuller House Twitter account, Cosmo died unexpectedly after having complications from a recent surgery. "There will never be another quite like our boy. We'll miss him forever," the tweet reads, accompanied by some photos of Cosmo's most memorable moments on the series. As the dog was a puppy in the show's first season which was filmed in the summer of 2015, we can surmise that he was just four years old.

Franchise star Candace Cameron Bure has also spoken about the sudden loss of the animal. "Cosmo has been in Fuller House since the start and we are heartbroken that he passed away," Bure writes on Twitter, noting that she imagines Cosmo is "running around in doggie heaven" and playing with Comet. Uncle Joey actor Dave Coulier has also commented on Cosmo's death with a touching Twitter post of his own. "He grew up [on] Fuller House and will be loved and missed forever," Coulier writes.

The decision to use a golden retriever as the family pet in Fuller House is a direct throwback to the original series. On Full House, the Tanner family adopted a goldie named Comet, who was played by the same pup who did the basketball comedy Air Bud. On Fuller House, it is explained that Cosmo is actually Comet's great-grandson, hence the similar name. As a puppy, the dog was brought into the family by D. J. Tanner-Fuller (Candace Cameron Bure) to help cheer up her son Max Fuller (Elias Harger) following the death of his pet fish. The canine then served the role of the family dog throughout all five seasons of Fuller House, with the same animal in the role for the entire series.

A direct continuation of the '90s sitcom Full House, Fuller House first debuted on Netflix in 2016. The series features many of the same characters from the original show returning to reprise their roles, with D. J. and her children moving into the old Tanner household in San Francisco with her sister Stephanie (Jodie Sweetin) and best friend Kimmy (Andrea Barber). Nobody could have predicted the success of the Full House sequel series, which proved to be a popular program for the streaming service. Fans of the show may be disappointed to see it soon come to an end after the conclusion of its fifth season, but as Netflix has become notorious for axing their popular programs too early, a five-season run on the streamer can be seen as a big success.

The first half of the fifth and final season of Fuller House premiered on Netflix earlier this month, and the remaining episodes will follow in 2020. Because the season has already completed filming, we can expect to see Cosmo appear in the show's final episodes, though seeing the golden retriever will be bittersweet. Rest in peace Cosmo - you were a good boy. This news comes to us from the official Twitter account for Fuller House.