(noun) - An old phrase of the days of the portable theatre, and one which still exists in the theatre world of today. It was used as a kind of code. The traveling or fairground theatre of the old days depended for its revenue on the number of shows it could get in during the period of the fair. If, while a performance was proceeding, a queue gathered outside which would fill another house, the showman called out from the door, "Is John Audley here?" This was a hint to the people on the stage to finish quickly and get rid of the audience to make room for those waiting outside.
--Edwin Radford's Encyclopædia of Phrases and Origins, 1945