Sonu is there only as a guest vocalist, lending his unique appeal to the song which can be called its USP as well as its highlight and also forms the background music in the promos. The extremely choosy and busy Sonu has made this (a sort of singing guest appearance!) an exception for the music maestro A.R.Rahman, whom he shares a great bond with ever since his Dil Se days right up to Yuvvraaj .
When the first visuals of the melodious romantic track, "Guzarish", from the Aamir Khan–Asin starrer, Ghajini were aired, almost everyone was unanimous that the melodious number was rendered by the king of love ballads, Sonu Nigam. To an extent they were right, and to an extent wrong! Right in the sense that the hauntingly beautiful humming in the beginning of the soundtrack is indeed by Sonu and wrong because Prasoon Joshi's lovely lyrics have been sung by Javed Ali of "Jashn-e-Bahara", (Jodhaa - Akbar) fame.