Shooting for the Saif Ali Khan – Rani Mukherji starrrer produced and directed by Kunal Kohli (Hum Tum) has begun more than a month back but the Chote Nawaab is yet to join the action. We found out why.

A unit source informed us, "This yet untitled flick bringing the Hum Tum combination, Saif-Rani-Kunal Kohli together is currently being shot at the Yash Raj studios in Mumbai. Saif has not shot for a single day here because of his changed appearance for another Yash Raj film that he is currently shooting for, Tashan. His look for Tashan has him sporting an unusual hair style with long side burns and a barrel moustache. He can't alter this look for the Kunal Kohli film and get back to his Tashan look in a matter of few days. Therefore, the makers have planned both the films' schedules in such a way that they don't clash and end up him having continuity problems."

Kunal had earlier told us, "Saif joins us for the film from October onwards."

"Right now Kunal is filming Rani's portions with Amisha Patel and other co-stars that also include a few child actors," the source further adds.

This film is supposed to be an inspired version of Hollywood hit, the children's classic, Mary Poppins, although Kohli doesn't admit it. Industry insiders claim it is as much inspired from the 1960s Julie Andrews – Dick Van Dyke starrer as much Kohli's Hum Tum was inspired from When Harry Met Sally. In this film, Saif sports a clean shaven look with a different hair style.

"There is a special promotional music video also going to be shot for Tashan in November for which Saif will be sporting the same look that he will have in Kunal Kohli's film," reveals another source.

- indya.com