"Our guest singer tonight is a blue-eyed Italian kid who's been makin' 'em swoon from Hackensack to Poughkeepsie! Ladies and Gentlemen, I'm proud to introduce Mr. Frank..."
Behind the scenes
Marion Ravenwood introduces Frank as "a blue-eyed Italian kid who's been makin' 'em swoon from Hackensack to Poughkeepsie!". Which suggests that she is introducing Frank Sinatra but he does not appear nor does she mention his last name. In reality, Sinatra had not really started his career at this time though he worked as a singing waiter in New Jersey he would not yet have achieved the status Marion attributes to him at this early date. Therefore, we must assume the reference is either an anachronism on the part of the author, or that the Frank she is introducing simply isn't Sinatra.