Harris, who thanks the audience "for enabling our ADD," has made several Broadway appearances, notably his Tony Award-winning turn in the title role of Hedwig and the Angry Inch, and hosted the annual Tony Awards broadcast.
Watch a video of his "End of Show Show" performance, most of it done in a single long take.
"Best Time Ever with Neil Patrick Harris" aired Tuesdays at 9 PM on NBC. For more information, click here.