"Sons of Anarchy" star Charlie Hunnam shows how he keeps his sexy physique in check in next month's issue of Men's Fitness -- and describes how his strength and a handy machete once stopped a burglar in his own house!

A couple weeks before his interview with the mag, Hunnam says he heard noises at his place at 1AM -- and that's when he picked up the giant blade he keeps in his office and confronted a man ransacking his pad.

“He was about 5'10", 245 pounds, a beast" says the 6'1", 180 pound actor, “I pinned him to the ground and said, ‘Dude, I’m not going to **** you up this time, but if you ever come near here again, literally, they’ll never find your body, I’ll cut you in so many pieces.’”

Not surprisingly, the guy never came back.

Check out Hunam in all his glory when the new Men's Fitness his newsstands October 18.