Kaley Cuoco Sings The Big Bang Theory Theme Song [Video] https://youtu.be/rQc8M2Dxwx8 Kaley Cuoco shows photos from The Big Bang Theory that prove she’s never working behind-the-scenes before taking some questions from the audience. Video courtesy of The Tonight Show Starring Jimmy Fallon. Previous Article On This Day in '66, 'Monkees' Filming Began Next Article On The Tonight Show: Wonder Woman [Video]