Kaley Cuoco Sings The Big Bang Theory Theme Song [Video] 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 The Fabulous Dali: An Amazing Tour with Acclaimed Architect Yann Weymouth