The political satire was slated to release in June this year but it got delayed. Hirani, who is also directing the film, had earlier said that most of Aamir's films release during Christmas and they have done well.
The superstar's blockbusters like Dhoom:3, 3 Idiots and Taare Zameen Par had hit screens around Christmas.
P.K. also features actor Sanjay Dutt, Anushka Sharma and Sushant Singh Rajput.