It was just another day at the office when Harry Letterman, five, stopped by "The Late Show with David Letterman" on Wednesday night.
Dave pointed out his waving son in a balcony over the stage saying, "Hi Harry! Ladies and gentleman, it's my son Harry!"
A few minutes later, Harry interrupted his dad, blowing kisses and calling out "bye!" Dave waved back and said, "Thank you sweetheart, thanks for stopping by," and Harry walked out.