Rascal Flatts guitarist Joe Don Rooney can't be blamed for playing a somber six-string this weekend. He and wife Tiffany Fallon had to say goodbye to their dog on Monday. A post on his Twitter page reads, "We miss our Stevie so much! RIP Stevie Ray Rooney 8.15.11. Sweetest dog ever put on this earth!"

The 15-year-old French Mastiff was a friend to Rooney long before his rise to country superstardom with Jay DeMarcus and Gary LeVox. "170lbs of Happy Valentine's Day love for y'all right here! Come & get it!" Rooney wrote in an earlier tweet. Friends and fans of Rooney's have already begun expressing sorrow for the couple.

The trio continues their Flatts Fest tour this weekend with two shows in Florida, before playing the Grand Ole Opry next Tuesday. Rooney and Fallon have a 3-year-old son named Jagger and a daughter named Raquel, who turns one next month.