Three years ago, Alex Minsky was a 21-year-old U.S. Marine from Venice Beach, California.

He got caught in a roadside bomb explosion while serving in Afghanistan, and ended up spending 47 days in a coma. He also lost his right leg.     Alex was awarded the Purple Heart and sent home, and since then, he's battled depression and a drinking problem.

He finally decided to try to go an entire day without getting drunk . . . and it just happened to be the day when a photographer saw him at the gym.

So the guy had him pose for some pictures . . . and that led to Alex's new career as a SMOKING-HOT underwear model.

Check out his amazing story...