The 72-year-old actor plays father to actress Deepika Padukone in this Shoojit Circar's film, which also stars Irrfan Khan.
"The shoot for the PR of 'Piku' has begun and there are some most unusual works being done. Today we were a part of it along with Deepika and Irrfan.
"Unfortunately I am not permitted to expose them here, but may I just say that they all look rather unusual and hilarious...!" he wrote in his blog.