Louis and his friend were strolling when our photog asked him about his recent comeback gig at the famed Comedy Cellar in NY's Greenwich Village. Something about the question made him LOL on the spot.

We didn't exactly get an answer, but it's obvious he's in a great mood. As we reported, a few people in the audience were upset when Louis made his surprise appearance -- but, for the most part, he got a rousing applause.

This is the first time we've gotten him out and about since last year's sexual misconduct scandal, for which he apologized.