Actor Aamir Khan says his role in upcoming comedy-drama PK is one of the most challenging roles in his more-than-two-decade-long career.

The 49-year-old actor released the Rajkumar Hirani-directed film’s first trailer on the occasion of Diwali on Thursday.

“I have been working for the last 25 years and PK is by far the toughest role in my career. I have not blinked in the movie. We had discussed a lot about shaping my character but we felt everytime that something is missing,” Khan said.

In the film, Khan’s character is an admirer of betel leaves. “PK is fond of paan [betel leaves]. I am too. During the shooting of the film, I must have consumed about 100 paans. There used to be a paanwala [person who prepares betel leaves] on the set for us,” Khan said.

PK is the second collaboration between Khan and the National-award winning director after the superhit film 3 Idiots.

Hirani took five years to complete the film.

“When I was finishing 3 Idiots, I realised that I should start my next film. At that point of time, Abhijat [Joshi] and I went for a walk at Borivli National Park [in Mumbai]. And there we thought of PK. Abhijat then went to the US.

“We used to discuss the topic and thus the film happened. It took five years to finish because the script took a long time as we tried to convey a strong message in an entertaining way,” Hirani said.

Anushka Sharma plays the female lead in the film and will be seen in a new look. “I am very excited to play the role in PK. When we were doing costume trials, we went for different looks with wigs and glasses. And finally when the look worked out, I am getting a lot of compliments. All girls now want to have a hairstyle like me,” said Sharma.