A birdie tells us that the Masakali track from Rakeysh Omprakash Mehra's Delhi-6 was originally composed for Farah Khan's Om Shanti Om.
A R Rahman was initially supposed to score OSO's music. But things didn't work out and Vishal-Shekhar were roped in. Now we only wonder how Shantipriya (Deepika Padukone's character in the film) would have done a Masakali sans a pigeon?
http://mid-day.com/entertainment/2009/jan/220109-Vidya-Balan-Neha-Dhupia-Sonali-Kulkarni-Gitanjali-Luxury-Farhan-Shah-Rukh-Konkana-Sen-Ranvir.htm
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