Mel enjoyed decades of success, having released over 60 albums and dozens of top ten singles over the years.
The singer-songwriter's publicist Don Murry Grubbs confirmed the tragic news, with his suspected cause of death believed to be respiratory failure. Many of those songs were recorded by other country music stars such as Kenny Rogers, George Strait and Ricky Skaggs.
Born Lonnie Melvin Tillis in Tampa, Florida, he suffered a spell of malaria as a boy that left him with a chronic stutter, according to the Country Music Hall of Fame. He grew up in Pahokee, near Lake Okeechobee, and briefly attended the University of Florida.
A representative for Tillis' daughter Pam Tillis, also a country singer-songwriter, wrote on her Facebook page that his death was "sudden and unexpected". In February of 2012 President Obama awarded Tillis the National Medal of Arts. His stutter became a trademark that Tillis mined for laughs, although it disappeared when he sang.
Mel - best known for hits including I Ain't Never and Good Woman Blues - had reportedly been battling an intestinal issue since past year.
Tillis was a familiar screen presence in the '70s and '80s, with small roles in films including "W.W. and the Dixie Dancekings", "The Villain", "Every Which Way But Loose", "Smokey and the Bandit II", and both "Cannonball Run" movies. TV guest spots were frequent, including a debut acting appearance on "Love: American Style" in 1973, followed by shows like "The Dukes of Hazard", "The Tim Conway Show", and "The Love Boat".