The folksy song is sung by a singing reality TV show participant Swaroop Khan, composed by Ajay-Atul and written by Swanand Kirkire, who were also present at the press conference.
With peppy beats and energetic movements, the song showcases Rajasthan's traditional flavours as it highlights the camaraderie between Sanjay Dutt and Aamir.
In the song, Sanjay is seen prancing around a confused Aamir, who gets attracted to hands irrespective of gender and is seen running to grab them in the video, and asking him to behave himself.
The song brings forth a sense of Rajasthan alive on screen with the desert state's by-lanes, brightly-coloured clothes, dance movements and rustic flavours amalgamated into one fun track.
"The reason we are releasing the song in Delhi is because a major chunk of the movie is shot in Delhi. The special thing about the song is that it has two of my favourites- Sanjay Dutt and Aamir Khan," said Hirani at the launch in Spice Cinemas here.
The word "tharki" means lecherous, but Aamir insists the word is used in a "humourous manner and should not be taken otherwise".
"I enjoyed working with Sanjay, who is like an elder brother to me. It was a memorable experience," he added.
The actor, who has rolled out several performance based films like "Taare Zameen Par", "Lagaan" and "Ghajini" also confessed that "P.K." is the most challenging film he has done till now.
"The film is the most challenging film I have done in my career. I would place all the roles I have done till now on one side and the role of 'P.K.' on the other side," Aamir said.
Another page from the story of "P.K." was unfolded, the song evinced that Aamir's character has amnesia and is seen wandering around in the movie.
However, the cast declined to answer questions asked by the media persons about the film.
"In order to make the viewing experience of the audience better, we want to keep the story of the film under wraps," said Hirani.
The film, which also stars Anushka Sharma and Sushant Singh Rajput, is slated to release Dec 19.