David Hasselhoff Breaks Out 'Baywatch' Beach Body

David Hasselhoff was back on the "Baywatch" beach ... teachin' the youngins a thing or 2 about fake lifeguarding.

The 63-year-old showed up on the set Tuesday in Savannah, Georgia, giving pointers to The Rock on how to properly jog on the beach, before sitting down to enjoy a couple of ice cold beers.

The Hoff jawboned it with Zac Efron ... then took pics with a random couple who got married on the sand.