http://www.playbill.com/news/article/double-duty-how-broadways-best-juggle-eight-shows-a-week-and-a-solo-cabaret-on-the-side-378843
"Noel [Coward] and I were in Paris once. Adjoining rooms, of course. One night, I felt mischievous, so I knocked on Noel's door, and he asked, 'Who is it?' I lowered my voice and said 'Hotel detective. Have you got a gentleman in your room?' He answered, 'Just a minute, I'll ask him.'" (Beatrice Lillie)