Is the riddle essentially asking:
How do you make a celebrity run/drive away like a chicken, as fast as he/she could?
In that case there are too many ways... Such as approaching them with your fingers in your coat pocket emulating the shape of a pistol, or wearing a raincoat and making the impression that you're wearing nothing underneath, and are about to unbutton and pull open the coat (okay, that might not work on some celebrity, such as Paris Hilton)...
Sorry, I know this is not supposed to be a joking riddle, but couldn't resist...