Bollywood superstar Aamir Khan, who kept mum on speculations about his role in Rajkumar Hirani's "PK," has finally opened up.  A lot has been written and spoken about Aamir Khan's role in "PK" with each promo triggering fresh speculation. Some said he is playing an alien in the movie, while others said that he must be an autistic. The makers of the film have been silently enjoying the speculations all these days. They essentially  wanted to build viewers' curiosity about the film. Finally, Mr Perfectionist himself spoke, with the revaluation coming while talking to journalists in London through video conferencing, which was organized by UTV Motion Pictures at the Court House hotel. Aamir Khan denied that his role was about autism. "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," said the 49-year-old Bollywood actor as saying. He then revealed that he plays a stranger in the city and "PK" is a comedy of ideas about the stranger, who asks questions that none has asked before. The movie is about a friendship between strangers from worlds apart. "PK" is the latest offering of superhit "3 Idiots" fame trio Aamir Khan, director Rajkumar Hirani and producer Vidhu Vinod Chopra. Anushka Sharma, Boman Irani, Saurabh Shukla, Sushant Singh Rajput and Sanjay Dutt are playing important roles in the movie, which is slated to release in theaters on 19 December.