Megastar Amitabh Bachchan, who is back to hosting the sixth season of the popular game show 'Kaun Banega Crorepati', believes that knowledge is the key to success. With the "power of knowledge" as the central theme, the makers of the 'Kaun Banega Crorepati' announced 'Sirf Gyaan Hi Aapko Aapka Haq Dilata Hai' as its communication theme for the sixth season of the show. "As per our tagline of this season, 'Gyaan Hee Aapko Aapka Haq Dilata Hai', those who come to the hot seat will have to be knowledgeable," Bachchan told reporters here.