If we ever find out that Post Malone ISN'T the coolest celebrity ever, we’re gonna be crushed . . . because he totally gives off that vibe.

Case in Point:  After a show on Friday night, he helped a couple with their GENDER REVEAL. 

And he seemed genuinely excited to be a part of their big moment. Post was signing autographs from the stage, when they handed him an envelope with the sex of their baby inside and asked him to do the honours. 

And of course, he did.  It's a girl, by the way.