"Elvis has left the building"--origin?

I seem to remember that this was used at an Elvis concert (concerts?) back in the day when he had such rabid fans that this announcement was necessary in order for the venue to clear out. Can anyone validate this?


Salt & pepper are married!
on Blues Clues.
They ahd a child, Cinnamon!

Note: this is in reference to the silly question after the Elvis one in cecil’s column.