Boo, allegedly the world's cutest dog, has died.

His owner posted on Saturday, Jan. 19 (Singapore time), about news of the Pomeranian's demise:

"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."

Boo was 12 years old. Records indicate his birth date was in March 2006.

Over the past decade, he became a social media sensation due to his retaining of his infantile look -- also known as neoteny -- and resembling a baby bear.

Boo's official Facebook page has more than 16 million followers.

Boo's owner also wrote:

"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."

Over the course of his lifetime, Boo's image has been licensed for use to spawn an array of merchandise sold globally.