Context

This famous line is spoken by Jack Torrance, played by Jack Nicholson in The Shining (directed by Stanley Kubrick, 1980).

Ah, Johnny Carson. The comic everyman. Everyone's favorite late night talk show host. He came into our living rooms each evening and made us feel as if he was a good, dear friend. What a sweet, brilliant man.

How honored he must have been to have the line usually associated with him and his show become famous...for one of the most truly frightening moments in all cinema. 

You didn't see that one coming, did you, Ed McMahon?

In The Shining, a deranged man is chasing his wife with an ax. As he hacks his way through the bathroom door and sticks his head through, eyes bulging and teeth bared, he lets loose with a "Heeeeere's Johnny!" It's made all the more terrifying by the fact that the original line was so innocent. Johnny never threatened anyone with an ax.

And supposedly, Nicholson actually improvised the line. 

Nice job, Jack.

Where you've heard it

Well…The Tonight Show, obviously.

There was a 1992 song (if you can call it that) by the group Hocus Pocus with the same title—and you can even hear Jack's line being delivered at about 40 seconds in (and again at the 2:06 mark).

It's gotten plenty of love from all sorts of people…like whoever decided to make this Minecraft version.

And, of course, if you and your friends ever tried to make a fort in the living room as a kid, chances are good your older brother stuck his head through the sheets at some point and did his best to scare the living daylights out of you by saying the line himself.

Pretentious Factor

If you were to drop this quote at a dinner party, would you get an in-unison "awww" or would everyone roll their eyes and never invite you back? Here it is, on a scale of 1-10.

Terrifying, yes. Pretentious? Not really. Unless you follow it with a dissection of Kubrick's camera angles.