David Letterman's monologue was interrupted by a reckless heckler Monday night who revealed himself to be Chicago Cubs sportscaster Harry Caray. Or, rather, Will Ferrell doing his timeless "SNL" impersonation of the late legend.
"Hey! Isn't it true you're retiring, Ed?" Ferrell says to Letterman, after forcing his way onto the stage.
"Yes … half of that is right, Harry," Letterman fires back.
"That's a good call. I could tell you were losing a little mustard off the heater," Ferrell says.
And that's how you do a Letterman send-off.
Watch the clip below: