From Nookipedia, the Animal Crossing wiki
K.K. Chorale is a K.K. Slider song. It is quite a soft and classical song. Cookie (in Animal Crossing: City Folk), Kitt, Alli and Chevre all play this song if they have a stereo in their homes. On the Animal Crossing-e card, it shows K.K. Slider being married to Daisy, with an audience watching.