"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 (Padukone) and Irrfan (Khan). Unfortunately, I am not permitted to expose them here, but may I just say that they all look rather unusual and hilarious," the 72-year-old wrote on his official blog srbachchan.tumblr.com Monday.
Big B will be seen playing the role of Deepika's father in the film, which is directed by Shoojit Sircar, and majorly shot in Kolkata.
Meanwhile, remembering the shooting days of 1976 drama-thriller film "Do Anjaane", Amitabh also posted a black and white photograph in which he is shooting for the song "Luk chup luk chup".
"This is Calcutta 1975 and the shooting of a delightful film 'Do Anjaane'. 'Deewar' had just released the previous day of travel to the city and the reception at Grand Hotel and the city was phenomenal...getting in and out of the Hotel was an army operation," he wrote.
"This moment was the shooting of a song 'Luk chup luk chup jaao naa...' with the little kid. It was shot at the famous Botanical Gardens across the river Hoogly," he added.
Big B says he used to carry a camera with him to capture moments on shootings. In the photograph, he is seen clicking the crowd on the other side of the lake.