Willie Nelson might use a multi-colored guitar strap, but he'll soon be wearing a new black belt.

The country legend will receive his fifth degree black belt in the modern Korean martial art of Gong Kwon Yu Sul in a ceremony in Austin, Texas on April 28th -- just before his 81st birthday. Willie's teacher, Grand Master Sam Um, admits the singer is not the typical student. 

Local reports indicate that most people stop training in their 40s, while Nelson began studying the mixed martial art in his 60s. 

Um adds that Willie "has great discipline," and when he's on the road he'll send Um videos of his practices for critiques. He also admits that Willie now has a higher rank than he has, and that Nelson "could take" him "in a fight with no problem."