Dan + Shay's Dan Smyers and his wife Abby adopt senior dog facing 'serious medical concerns'

It’s a well-known fact that Dan Smyers of Dan + Shay and his wife, Abby, are huge dog lovers and passionate advocates for shelter pets.

Last week, they added a fifth member to their pack by adopting a 16-year-old 2-pound chihuahua.

"16 years old. Emaciated. No teeth. Etc. All alone and terrified at the shelter," Smyers wrote on social media, along with a slideshow of pictures of his furry new family member. "We weren’t going to let her live the rest of her life like that."

The couple started out by fostering the chihuahua, who goes by Missy, Tiny or Little Dog, according to an introduction post on Abby’s Instagram.

But after getting some worrisome news from the vet about her health, the Smyers decided to make the little foster dog a permanent addition.

"She was dealt a tough hand in her previous life, but we’re going to make up for lost love the rest of the time she has left," the singer wrote in another post. "We’re unsure of whether she had a family before, but we’re happy to say that she does now as we’ve decided to officially adopt her as our 5th dog."

As for the other four dogs -- Joy, Chief, Ghost and Mac -- who call the Smyers' household home?

"They have been so calm around her and let her 2 pound self take an entire couch," Abby shared.

When not spreading love and positivity to animals at home, Dan Smyers is spreading musical love and positivity with his bandmate, Shay Mooney.

The pair recently shared their newest single, a message of gratitude toward their fans called "Glad You Exist."