
Sleepy kitty, happy kitty, purr purr purr." The song remains part of Play School 's catalog of children's songs regularly performed on the program: the show's presenters occasionally perform the song for their young viewers. Versions of the song have been released by Australian children's performer Patsy Biscoe, and by the long-running ABC children's program Play School -a recording sung by Philip Quast and Barbara Frawley was released on the show's 1993 album The Best of Play School, which predates The Big Bang Theory and has the lyrics reversed, instead going: "Warm kitty, soft kitty, little ball of fur.


Władysław Syrokomla and pl:Wiktor Każyński published a version of this song in 1857, in Pieśniach ludu polskiego ("Songs of the Polish people"). The lyrics were noted by folklorist Oskar Kolberg in 1937, when the tune was first published by Stanisław Moniuszko in 1849, based on a Polish folksong. The song is originally based on a Polish lullaby, Wlazł kotek na płotek ("The kitten climbed the fence").

Wlazł kotek na płotek as it appears in Pieśniach ludu polskiego (1857)
