Willie Nelson has added one more line to his already incredible resume.

The Grammy-award winning singer/songwriter, who has also put in time as an actor and activist, is now a fifth-degree black belt in the martial art of Gong Kwon Yu Sul.

Nelson has practiced martial arts for some 30 years, and he decided that there would be no better time to earn a new black belt than on his 81st birthday on April 29). In front of a room in Austin, Texas, packed with other students and even Austin native Lance Armstrong, Nelson was awarded a belt personalized with his name.

"Honestly, I was surprised to be getting this degree," Nelson told the AP before the ceremony. "I don't know what else is out there. I never thought about anything beyond second-degree black belt."

Nelson has always maintained an active lifestyle, and growing up he played baseball, football and ran track. He credits his exercise with keeping him lively as an octogenarian.

"I'm pretty healthy at 81. I think a lot of it has to do with the exercise that you do," Nelson said. "I think martial arts is one of the best exercises you can do. Mentally, spiritually, physically, everything. I'm sure that's helped."