ADORABLE: Clearly a huge "Frozen" fan, dog wakes up to his favorite song & howls along!

When your favorite song comes on the radio -- you've got to sing along, right?!

This puppy was sleeping soundly in the backseat of a car -- but when he hears the first few notes of his favorite song, he's up and at 'em!

Apparently, this guy (like so many others) is a HUGE fan of Disney's "Frozen."

Watch as he howls along with his favorite song, "Let It Go:"