"My best friend died yesterday," the singer, 31, announced on Twitter Friday of her adopted dog's passing, saying, "Joplin was special. He fought his whole life to survive & now he can rest. I loved him."
Clarkson thought she lost her BFF almost two years ago, when Joplin ran away on New Year's Eve.
"I lost it ... and started bawling when [my sister] told me [the dog was missing]," she shared. "Seriously, I was so dramatic ... but I don't have children and [my dogs] are my babies that I sleep with every night."
After fearing the worst, Clarkson found her little guy and called it a miracle, adding, "Yes, I might be too attached to my dogs and highly sensitive, but I don't care. I love them!"