Boo, the precious internet-famous Pomeranian, is dead at age 12

It's a sad, sad day for fans of the "world's cutest dog."

On Friday, the owners of Boo the Pomeranian announced on social media that Boo died in his sleep at the age of 12. The precious and beloved pup has hundreds of thousands of followers on Facebook and Instagram, and several books written about him.

Though Boo's humans are "heartbroken," they explained they're hopeful that Boo will soon be reunited with his best friend Buddy, who died in Sept. 2017.

"I brought Boo home in the spring of 2006 and so started the greatest, most heartwarming friendship of all time. Shortly after Buddy died, Boo showed signs of heart issues. We think his heart literally broke when Buddy left us. He hung on and gave us over a year. But it looks like it was his time, and I’m sure it was a most joyous moment for them when they saw each other in heaven."

"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," Boo's owners explained.

After the news broke, Boo's many fans mourned his death online and offered love and gratitude to his family for sharing his journey.

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"Since starting Boo’s FB page, I've received so many notes over the years from people sharing stories of how Boo brightened their days and helped bring a little light to their lives during difficult times. And that was really the purpose of all this," Boo's owner went on.

"Boo brought joy to people all over the world. Boo is the happiest dog I’ve ever met. He was so easy going that we never had to bother with training. He made the manliest of men squeal with delight over his cuteness and made everyone laugh with his quirky, tail wagging personality."

Boo's humans then proceeded to thank all of the loving fans, doctors, therapists, and animals hospital staff members that both Boo and Buddy encountered over the past 10 years.

Rest in peace, Boo. You will be missed.