Just because Gene Hackman retired from acting a few years ago doesn’t mean he can’t summon some of his signature grit when needed.

TMZ reports the 82-year-old Oscar winner had just left a New Mexico restaurant with his wife yesterday when they were approached and threatened by a homeless man named Bruce Becker.

The rest sounds like a scene from one of the actor’s tough guy films.

We’re told the incident escalated big time when Becker called Hackman’s wife a “c**t” — and then Hackman dished out some street justice … slapping Becker across the face.

Becker then called the cops to report the incident.

We’re told cops interviewed Hackman and his wife, determined the slap was in self-defense … and, for now, no charges have been filed.