Unpredictable rains have written themselves into the script of Deepika Padukone and Farhan Akhtar-starrer Karthik Calling Karthik. The film's unit is shooting their last schedule in Mumbai. Says writer-director-co-producer Vijay Lalwani says, "We had to rewrite the scene because it rained heavily last week. It was quite a surprise because normally, it doesn't rain in October and we had waited a month and a half for the monsoons to end."

Amit Chandra from Magic Beans Films (co-producer) adds, "It was very funny. Once Farhan and Deepika would arrive on the sets, it would start raining and when they went back to their vans it would stopped. Finally, Vijay had to rewrite the scenes and have the rains incorporated into it. It was written charmingly and Farhan and Deepika were very happy."

Lalwani adds, "We had waited for the actor's dates and they were on the sets when it started pouring. Rather than cancel the shoot I sat and rewrote the scene, which was a montage with music, asked for triplicates of their clothes as they would get soaked and dirty in the rain. We shot the scenes in a day. I didn't want to lose my artistes' dates. I even had a rain machine called in — in case if it stopped raining altogether." The romantic thriller releases in 2010.