Lambchops(1929)

George and Gracie enter an elegant drawing room, looking everywhere for something. Turns out, they're looking for the audience, and when George spots the camera, they start in on their patter. Gracie wants to convince George that she's smart, not dizzy - it's an uphill struggle of which she's blissfully unaware. Midway through, they break into song: "Do You Believe Me?" It includes a little bit of hoofing as the chatting continues. They end on a story Gracie whispers into George's ear.