Canine social media influencer Boo the Pomeranian has sadly passed away, his 'humans' confirmed on his Facebook page.
They said he would be joining his best mate Buddy - who also recently died - 'on the other side of that rainbow bridge'.
A Facebook post on Boo's page addressed to 'dearest friends of Boo' said: "With deepest sadness I wanted to share that Boo passed away in his sleep early this morning and has left us to join his best friend, Buddy.
"Our family is heartbroken, but we find comfort knowing that he is no longer in any pain or discomfort. We know that Buddy was the first to greet him on the other side of that rainbow bridge, and this is likely the most excited either of them have been in a long time."
The post explained that shortly after Buddy died, Boo had started to show signs of heart issues. Despite the fact that he 'hung on' and gave them over a year, he eventually passed away in his sleep.
"We think his heart literally broke when Buddy left us," Boo's 'humans' explained - adding that it must have been a joyous moment when the two pooches reunited in heaven.
Referring to Boo as the 'happiest dog' they'd ever met, his owners said their beloved pooch made 'the manliest of men squeal with delight' and brought joy to people all over the world.
The post continued: "Boo, we love you with all our hearts and will miss you until the day we meet again. Have fun running around with Buddy and creating adorable mischief wherever you guys go.
"Thank you to all of you for following along on their silly adventures over the past 10 years. They sure had a LOT of fun."
Boo, who was often dubbed the 'World's Cutest Dog' had a strong social media presence, having racked up well over 16 million followers on Facebook. He also released his own book, Boo: The LIfe of the World's Cutest Dog in 2017.
Many fans commented on the post to pay tribute to the four-legged legend, thanking his owners for 'sharing' him with the rest of the world.
One person wrote: "He was the cutest little boy I have ever seen! Prayers for your healing!"
Another said: "Thank you for sharing your precious Boo with the world. Sharing the light, love and happiness in little Boo's heart brought so much joy to millions around the world."
A third one: "I am writing this with tears running down my face. I loved Boo & Buddy like they were my own, even though I never met them."
Rest in peace, little guy.
Featured Image Credit: Boo the Pomeranian/Facebook