A spokesman for TV Store Online said Feb. 14 it has introduced a new exclusive officially licensed “The Big Bang Theory” T-shirt that not only shows the lyrics to the series' famous song “Soft Kitty” but actually sings it.
The shirt is soft gray in color and made of 60% cotton and 35% polyester, and includes an audio box (batteries not included) that sings soft kitty song with a push of a button. (There's a pouch to keep the audio box in, but, of course, it needs to be removed before washing.)
According to the plotline of the series, “Soft Kitty” is a song the mother of Sheldon Cooper (Jim Parsons) used to sing to him as a child when he was sick. The song has been used in several episodes, including one in season three, “The Adhesive Duck Deficiency,” when Penny (Kaley Cuoco), affected by some pain medications, asks Sheldon to sing it to her and they both end up singing it together.