Rehearsals for the sixth season of Kaun Banega Crorepati? (KBC) have started and Amitabh Bachchan, who will host it, is ecstatic as well as nervous. “Rehearsals for KBC begun… lovely to be among familiar faces and language. Now for the grind of performance… Such huge butterflies,” the 69-year-old tweeted Monday night. This game show will be aired on Sony, starting September 7.