Nag Ashwin’s 'Kalki 2898 AD' just days away, the makers hosted a lavish pre-release event in Mumbai. The event was attended by actors Prabhas, Kamal Haasan, Amitabh Bachchan, and Deepika Padukone. Recently Amitabh Bachchan shared a glimpse of his dedicated team from the event, posing with the starry cast. Big B disclosed the true reason for his involvement in the promotion