Heartbroken Boo, 'world's cutest dog,' dies aged 12

Boo, the world's cutest dog, has died of a "broken heart" after his companion died last year, his owners claimed.

The Pomeranian Boo and his companion Buddy became internet sensations when their American owners started sharing pictures of their adorable antics.

Boo and Buddy lived together for 11 years.

His death was confirmed in a post on Saturday by his American owners to his 16 million Facebook followers. He was 12 years old, in human years, CNN reported.

"Shortly after Buddy died, Boo showed signs of heart issues. We think his heart literally broke when Buddy left us," his owners wrote.

"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.

His owners, who are from the US, said Boo passed away in his sleep early Saturday morning and they were "heartbroken".

"Our family is heartbroken, but we find comfort knowing that he is no longer in any pain or discomfort," they added, noting that Boo "brought joy to people all over the world".

In addition to his social media presence, Boo was appointed in 2012 as Virgin America's Official Pet Liaison.

Boo made TV appearances, and even released a book called Boo - the life of the world's cutest dog which was published in 2011.