Aamir Khan, who is known to have played characters that are almost half his actual age (including a college student in Rang De Basanti (2006) and 3 Idiots (2009)) plays a character closer to his actual age, with graying hair, in this movie.
Aamir Khan is such a big name in India that he could not go in and out of the house that the shoot was taking place in without arousing huge public interest. So he and his wife Kiran Rao, who is also the director, actually stayed in the same house for the entire duration of the shoot.