The actor features nude with a strategically placed vintage boombox, and he has left audiences guessing what the Rajkumar Hirani movie will be about.
"What do you think guys? Tell me fast... butterflies in my stomach," Aamir posted on his Twitter page late Thursday night.
The poster elicited a roaring response from the Twitterati online, and several industry members too lauded the actor for pulling off such innovative stunts for his film's promotions.
Filmmaker Karan Johar tweeted, "Intriguing and brilliant first look of the much-awaited Raju Hiranis #PK."
"aamir_khan what a first look, gotta keep looking to figure ke yeh #PK hai kya," tweeted Kunal Kohli.
Composer Vishal Dadlani said, "That PK poster is MAD!! Already curious as hell about the film! Raju Hirani is the bomb, & Aamir has almost sixth sense-esque script-sense."
Aamir himself loved the responses and mixed guesses from people.
"Alien! Adi Manav! Drunkard! Just someone who has lost his clothes! Ha ha ha!!! Interesting guesses," Aamir posted Friday.
On Friday, a new clue about the character will be unveiled.
It has earlier been revealed that PK promotions will involve the use of talking standees, which will be kept in theatres, have the actor's photo and his voice installed in them.
When you go close to it, Aamir will speak to you.
PK also features actor Sanjay Dutt, Anushka Sharma and Sushant Singh Rajput.