The country music star and his wife, Caroline, are mourning the loss of Poochie, the Aussie mix they just adopted on Feb. 9 from the Nashville-area rescue organization Proverbs 12:10.
"If the kindest souls were rewarded with the longest lives, dogs would outlive us all," Caroline wrote on Instagram. "My heart is sad but full to post this..our sweet Prince Poochie has passed away. He lived 18 years and was loved by so many people."
The family bonded with the dog in a short time after adopting him from a foster home, where he was being cared for after having initially been "surrendered to the pound,'' according to Proverbs.
Luke had known the dog only a few days, but they were already becoming buddies.
The couple's two children, Bo, 10, and Tate, 8, also enjoyed their short time with Poochie.
"My kids especially loved to hear him snore when he slept!" Carolyn wrote on Instagram. "Thank you @proverbs1210animalrescue for giving our family the opportunity to love this sweet dog."
"While we would have loved for Poochie to have lived another 18 years, we are grateful for the time we gave him with our foster, Lacey Marie and with his adoptive family, the Bryans,'' Proverbs wrote on Facebook. "Poochie enjoyed his time with the Bryan family.
"He even felt well enough to stroll in their pastures and be a dog again. He sadly passed away a few days ago, but he was loved and passed in his sleep on a big comfy bed. He is now buried on the Bryan farm amid other beloved pets."
The Bryans are well-known animal lovers, with a host of dogs, cats, goats, chickens and even a pair of kangaroos that Luke gifted Caroline for Christmas two years ago.