Amitabh Bachchan has returned as the host of Kaun Banega Crorepati, and the 75-year-old megastar will steal your heart with his rap star avatar in the first trailer of the popular game show.The veteran star will ask you to register for the show in the coolest possible way as he dons a twin avatar and raps to 'Boojho to jaane bhaiya, yo. The expectations from Big B and the show's makers are on an all time high this time as the show's last season broke all rating records. The trailer also introduced the new theme for the reality show.