From Mark Evanier's Blog:
One of those hard-to-see (i.e., not currently available on home video) movies is Where's Charley?, the 1952 film version of the Broadway show of the same name. In the film, Ray Bolger reprised his acclaimed performance from the stage version ... and most folks are interested in this number, which is the show's big hit, "Once in Love With Amy." On stage, the song ran much, much longer. During tryouts, Bolger started expanding it ... and he would basically stop the plot and break character to chat with the audience and lead them in a sing-along each night. It became a famous theatrical moment and a lot of folks went to see the show just to see that twenty minutes or so.
The film version, clocking in at around seven, obviously does not replicate that experience but it's all we've got. It's still kinda delightful ...