Smiley, a blind therapy dog from Stouffville, Ont. as beloved by the internet as he was in real life, was euthanized on Saturday after a battle with cancer.
His owner, Joanne George, posted the news on social media on Saturday afternoon.
"He left us so quietly and peacefully in his favourite spot today at 12:30. I hope he is running free and can finally see the beauty around him," she wrote.
Smiley's owner says that masses were found in the dog's liver and stomach earlier this summer.
Smiley was born blind and rescued from a puppy mill in 2004. He has volunteered his services as a therapy dog for St. John's Ambulance helping those with disabilities, comforting them at funerals and aiding those with autism in learning to read.
These kids who were born with different disabilities are able to see that dogs, too, are born with the same disabilities.
"These kids who were born with different disabilities are able to see that dogs, too, are born with the same disabilities," George told HuffPost in 2015. "It's important for them to see that Smiley has overcome, and that he's happy."
Smiley's story had attracted international attention over the last few years, garnering media coverage on CNN, CBS and many other outlets. The 15-year-old therapy dog has almost 200,000 followers on his Instagram page.
The dog even met Prime Minister Justin Trudeau in 2016.
Tributes for Smiley poured in online. "Crying for a dog I have never met. You and your family have been so wonderful to share smiley with us all," Michelle Churcher wrote on the dog's Facebook page.
Dog humour Twitter account @dog_rates also paid tribute to Smiley.
Even more touching are the numerous dog owners who posted stories about pets they have lost. "My sweet Piper will welcome him. It is the hardest thing to let them go," posted Linia Perkins.
Others talked about how Smiley inspired them to foster and adopt dogs of their own.
"This is our sweet Charlie that we got to foster. He was left behind in the hurricane. We fell in love with him and have signed the adoption papers. Smiley is a huge part of why we have him," posted Kristin Marie Lively.