Megastar Amitabh Bachchan Tuesday morning rang the bell at the Bombay Stock Exchange as part of the promotions of "Yudh", a TV show which marks his debut in the fiction space on the small screen.Amitabh lit the welcome lamp along with N.P. Singh, CEO, Multi-Screen Media; Ashish Kumar Chauhan, managing director and CEO, BSE Ltd and Sudhakar Rao, chairman, BSE Institute Limited. He even revealed the striking poster of "Yudh", which follows the life of Yudhishthir, a real estate baron, who has recently been diagnosed with a degenerative neurological disorder.