"PK is not autistic. He has a reasonable approach to life. He does not blink. It is one of the toughest roles I have played in my career," the 49-year told actor told journalists in London through video conferencing organised by the film's distributor here UTV Motion Pictures at the Court House hotel.
'PK' is a comedy of ideas about a stranger in the city, who asks questions that no one has asked before. In the process pk makes loyal friends and powerful foes. Finally, it is a moving saga about a friendship between strangers from worlds apart.
The film, scheduled to hit theatres on December 19, is produced by Vidhu Vinod Chopra and Rajkumar Hirani, who has also directed the movie.
Besides Aamir, Anushka Sharma, Boman Irani, Saurabh Shukla, Sushant Singh Rajput and Sanjay Dutt also star in the film.
Oscar Award winner Resul Pookutty is the sound designer for the film.
Aamir said that Hirani is the force behind the film.
"This particular film was a special challenge to me and the experience of that journey is quite satisfactory. 'PK' has been really an amazing experience for me. The film has shaped up pretty much as we desired," he said.