The socialite issued a firm denial Tuesday in her newest episode of her "This is Paris" podcast ... saying she wasn't pregnant, and probably wouldn't be until she says her "I dos," which probably isn't too far away at this point -- as you know, she's currently engaged.

Paris had a joke-y way of coming out with the non-news ... at first saying she was expecting, and that she had triplets cooking in her gut. She pulled a big psyche right after that, though, and told the real truth -- namely, that there were no babies on the way, at least for now.

PH says she was getting blown up with questions about an alleged pregnancy -- which probably came about after one outlet straight-up said she was actually pregnant ... citing unnamed sources. Turns out, there's no truth it.

Some outlets keyed in on TMZ video shot last week, and speculated one angle made her look pregnant -- despite there being no indications she was -- but apparently, she looked different enough for people to wildly theorize she was pregnant.

Throw in the fact that she and her fiance, Carter Reum, have been undergoing in-vitro fertilization treatments as they prepare to be wed ... and you got yourself a rumor mill that's all of a sudden out of control.