April 29, 2014 at 5:42 PM ET
Don't mess with Texas — or Texas-born Willie Nelson. On Monday, the legendary singer, whose "Heroes Have Always Been Cowboys," received his fifth-degree black belt in the martial art of GongKwon Yusul.
Nelson, who turned 81 Tuesday (though sometimes April 30 is given as his birthday), tweeted a series of photos from the event.
"I'm pretty healthy at 81," Nelson told the The Associated Press. "I think a lot of it has to do with the exercise that you do. I think martial arts is one of the best exercises you can do. Mentally, spiritually, physically, everything. I'm sure that's helped."
Grand Master Sam Um has been teaching Nelson for 20 years, and said he was at first worried about whether the musician's heart could stand the strain of the workouts. Not any more.
"He has more stamina than I do," Um told the AP.
And what now for Willie? Obviously, he'll go "On the Road Again." After celebrating his birthday with a Tuesday-night concert at the Back Yard in Bee Cave, Texas, Nelson has a full list of shows lined up with singer Allison Krauss, who at 42 is just about half Willie's age.
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