Mumbai, June 26 : Actor Amitabh Bachchan promoted his upcoming film 'Bbuddah Hoga Terra Baap' (Your Dad might be old!) in entertainment capital Mumbai on Saturday.In the movie,Bachchan essays the role of a retired assassin based in Paris. He is asked to return to India for one last assignment, where he comes face to face with his past.Bachchan said the movie was completed within two months and