Looking at Belle on Cam2 I can only say "Smile!!! You're on Candid Camera!!!
The show involved concealing cameras filming ordinary people being confronted with unusual situations, sometimes involving trick props, such as a desk with drawers that pop open when one is closed or a car with a hidden extra gas tank. When the joke was revealed, victims would be told the show's catchphrase, "Smile, you're on Candid Camera."