<P> "Warm Kitty" is a children's song, popularized by the characters Sheldon and Penny in the American sitcom The Big Bang Theory where it is rendered as "Soft Kitty". According to claims in a copyright lawsuit, the words to "Warm Kitty" were written by Edith Newlin . The original version is a very popular Polish traditional lullaby "Wlazł kotek na płotek", a folk tune from the 18th century . </P> <P> In The Big Bang Theory, the song is described by Sheldon as a song sung by his mother when he is ill . The lyrics on The Big Bang Theory are: "soft kitty, warm kitty, little ball of fur! Happy kitty, sleepy kitty, purr purr purr!" A scene depicting the origin of the song in Sheldon's childhood is depicted in an episode of Young Sheldon, the prequel series to The Big Bang Theory . This aired on February 1, 2018, and shows Sheldon's mother Mary singing the song to her son, who is suffering with the flu . </P> <P> Versions of the song have been released by Australian children's performer Patsy Biscoe, and by the long - running ABC children's programme Play School which predates The Big Bang Theory and has the lyrics reversed, instead going: "Warm kitty, soft kitty, little ball of fur . Sleepy kitty, happy kitty, purr purr purr ." The song remains part of Play School's catalogue of children's songs regularly performed on the program: the show's presenters occasionally perform the song for their young viewers . </P> <P> By Christmas 2011, "Soft Kitty" merchandise--such as a plush stuffed singing cat, or T - shirt with The Big Bang Theory version of the lyrics--could be purchased . </P>

Nice kitty soft kitty little ball of fur