Conor McGregor is about to come face-to-face with his big rival, Dustin Poirier ... with both fighters set to show up at their final press conference in Vegas before UFC 264!!!
Of course, if you've ever seen a McGregor presser, you're in for a helluva show -- the guy dresses to the nines and speaks his mind ... pulling out all the stops to try and get in his opponents' heads.
Poirier, on the other hand -- he's a laid-back dude .