Meanwhile, trade experts believe the movie could well be on its way to touch Rs.300 crore and turn into Bollywood's biggest ever entertainer.
"@RajkumarHirani and @aamir_khan #PK is a masterpiece wid great entertainmnt value&message.Can turn out to be bigest ever of Bolywood so far," Mumbai-based trade analyst Komal Nahta tweeted Friday.
Another expert, Amod Mehra, conjectured: "Oh My God.. #PK is sureshot SUPER DUPER HIT.. Will break all records...Will cross 300 crores...200 in 1st week."
Girish Johar, who keeps a pulse on the business of cinema, shared Friday that "'PK' has (had) a huge opening at all premium sites and top end cities. In mass regions, it is above average....Overall, very good start in early shows."
Theatres are also happy with the response to the film, which also stars Anushka Sharma in a new avatar.
Devang Sampat, business head (strategy), Cinepolis India, said: "With 110 screens of Cinepolis (in 16 cities), we have been running approximately 500 shows in a day. All shows are running 90 percent plus occupancy. 'PK' is a much awaited movie of the year and the word of mouth is positive.
"We expect that the movie will do more business in the second week as well."
Kapur says on Twitter that "PK" finally gives Hindi cinema a "film where people are talking about quality of film rather than box office numbers".
Karan, a celebrated director himself, has commented that "'PK' yet again proves that Rajkumar Hirani is the best director of our country".
Lauding Aamir, Karan added: "It's undoubtedly Aamir Khan's best performance to date. 'PK' is hilarious and emotional in equal measure...it's a game changing film....Kudos to the team!!! @AnushkaSharma you were superb."
Critically acclaimed actor Atul Kulkarni notes that "PK" is a "bravo" attempt at "an entertaining statement, which requires guts to make and open mind to see".
The movie, which is said to be about a stranger in a city who asks strange questions, has also struck a chord with younger actors in Hindi filmdom.
After watching the entertainer at a special screening held in Mumbai Thursday night, Neil Nitin Mukesh tweeted: "Watched the screening of 'PK'. An outstanding film!!! Aamir Khan is an institute. Simply loved him. Bigger fan of Rajkumar Hirani after this.
Mr. Vidhu Vinod chopra take a bow for being an impeccable producer. #Respect
Actress Sonam Kapoor too seemed to be bowled over by the film, as she tweeted: "Overwhelmed by the film that is 'PK' what a movie.. Thank you so much #rajuhirani for it! Everyone has to watch this film!! No one but @aamir_khan could have done 'PK'! You made me cry and laugh out aloud innumerable times. Anything that I say is less."
From the critics' point of view, veteran Bhawana Somaaya says that while many would want to compare the movie to "3 Idiots", it's unfair to do so.
"People are asking me if 'PK' is as good or better than '3 Idiots'. Not fair to compare. They are different films, different genres," she tweeted, and added: "First time as a critic I feel some films are better experienced as a discussion rather than as a critical analysis and 'PK' is among them.
Somaaya even said: "Aamir Khan has done many challenging roles in his career, but 'PK' is beyond imagination. His performance has to be experienced."