Playbill eavesdropped on Broadway favorite Cheyenne Jackson (Xanadu, Finian's Rainbow, "30 Rock") rehearsing with New York Pops music director Steven Reineke as they prepared for the Nov. 18 Pops concert Cheyenne Jackson's Cocktail Hour: Music of the "Mad Men" Era. Expect the sounds of the 1950s and '60s — big and brassy numbers, sensuous bossa nova and tender, scaled-back guitar-and-voice renditions of classics. Jackson gives a sample with an intimate version of Irving Berlin's "What'll I Do?" Read the Playbill.com story.