Zac Efron -- 'Bodyguard' Claims Zac Saved My Life

Zac Efron was a hero who risked his own life to save the life of his "bodyguard" -- so claims the bodyguard.

We spoke to the "bodyguard" who says he and Zac were "cruising" around downtown L.A. Sunday at 12:30 AM, when they suddenly ran out of gas and rolled to a stop at the bottom of a downtown L.A. off-ramp.

Later in our conversation, the man -- we agreed not to use his name -- said it wasn't so much "cruising" as it was going to a restaurant in Little Tokyo in the downtown area.

TMZ broke the story ... Zac told cops they had run out of gas and for some reason threw a bottle out of the car which shattered and angered some nearby transients. Zac claimed the transients attacked the man and as Zac went to help him a transient viciously struck Zac in the face.

He tells us ... the transients actually went after him with "a spear" -- like a shank -- and stabbed him in the face, stomach and chest. He says Zac then got out of the car and swung a vodka bottle at the transients to fend off the attack. He says Zac actually thwarted the attack and saved his life.

So the man says the bottle Zac claimed to have thrown out the window wasn't really thrown at all. He says Zac used it as a weapon during the attack.