Directed by Rajkumar Hirani and produced by Vidhu Vinod Chopra, the film released Friday.
Girish Johar, who is aware of the economics of the Hindi film industry, tweeted: "#PK does a 50crs+ in flat 2 days - is now the 4th film of 2014 to get 50crs in 2days - #HappyNewYear #PK #SinghamReturns #Kick"
The film, which also stars Anushka Sharma, Sushant Singh Rajput and Sanjay Dutt, did better on second day by earning Rs.29 crore, said Rajesh Thadani of Multimedia Combines.
"It has collected at least Rs.55 crore in first two days. On the first day, it earned about Rs.26 crore. The next day, it managed to mint Rs.29 crore. They will earn profit, but expectations were higher," he told IANS.
"The film is being liked by people in metropolitan cities. It will maintain steady figures in coming days," he added.
Impressed by "PK", writer Milap Zaveri predicts a "huge run" at the box office.
"#PK has great growth on Saturday! This film is set for a looooong and huge run at the box office," he tweeted.