Boo the popular Pomeranian dies of broken heart, owners say

Boo, who was known as the "world's cutest dog," died at the age of 12, his owners announced in an Instagram post.

The beloved Pomeranian's passing was also posted on his Facebook page, which has 16 million followers.

His owners said Boo showed signs of heart issues after his lifelong companion Buddy died last year. They said Boo likely died of a broken heart.

The pair became internet sensations after their owners shared pictures of their fluffy and adorable antics on social media.