If you have not seen this rare footage before (or even if you have), you are in for a real treat. It starts around the 1:23 mark following some info on Chaplin's participation in the Third Liberty Loan Drive.
(The first photo of Chaplin shown in the video was actually taken after finishing The Immigrant, not A Dog's Life. I write about it here.)
Don't miss all the other familiar faces on stage with Charlie: Edna Purviance, Henry Bergman, Loyal Underwood, Albert Austin, and Tom Wood.