Recently, films like "Udta Punjab" and "Great Grand Masti" were leaked online even before they hit the screens.
When asked about her views, Kangana told reporters here last night, "That's very sad for our industry, we work very hard. I think it is violation and people should stop doing it."
The "Queen" star said one should not encourage the practice of piracy as it is nothing but stealing.
Imtiaz, who is gearing up for his next film with Shah Rukh, said it is a grave crime and people who indulge in it should understand that.
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"It's a very sad thing. People do not understand what kind of a serious crime it is. The audience who indulge in piracy also does not realise how it is hurting the actors, directors, movie-makers...They should really think about it. It is very harmful for the film industry," the "Tamasha" helmer said.
"Piracy should not happen. Don't ask me such deep questions at night. Ask me some simple questions," the 50-year-old "Dilwale" actor said.
The actors were speaking at a special screening of Irrfan Khan's film "Madaari", which releases tomorrow.
Irrfan, who was also present at the screening, said piracy has become a bigger threat to films than Hollywood.
"That's a huge threat, biggest threat. Piracy is a bigger threat than Hollywood, the way it is leaking online. I wish all the film industries of different regions can come together and ask the government that we need to stop it," Irrfan said.