Megastar Amitabh Bachchan has reunited with cinema icon Kamal Haasan after almost four decades, as the shoot for the much-anticipated sequel to 'Kalki 2898 AD' has begun. Big B took to his blog where he shared a string of pictures from the sets of 'Kalki 2' in the character of Ashwatthama. He also shared pictures with Kamal Haasan.