The 49-year-old director also said that he is busy exploring locations in Delhi for the film.
"I have been on location hunt in interiors of Rajasthan and Delhi. Songs are being recorded for 'PK'. All my energies are focused on the film. Nothing has changed. I wanted to capture the winter of Delhi and that's when we start shooting. We are on schedule," Hirani said in a statement.
The second unit of the film has already started shooting on schedule almost 15 days back.
The actual principal shooting with talent would start in mid January.
"Aamir Khan and Anushka Sharma join the shooting in mid January. We would be announcing a young dynamic actor in the second lead in a week's time," Hirani said.
It is for the second time that the 'Munnabhai' director is teaming up with Aamir after the blockbuster success of '3 Idiots'.