singers: Unnikrishnan, Bombay Jayashri
This is the first song of the film. It is a period of great happiness for Anandan (Mohanlal), for he seems to have finally landed his big break, working as a 'hero' for the first time and he has also just married Pushpa (Aishwarya Rai, version 1). The song is principally structured as a duet for that film-within-film featuring the leads (Madhubala in a guest appearance) while masterfully cutting back to real-life to the locally honeymooning (!) couple, with Anandan showing off some his histrionics to his new wife.
The setting seems to be from the story of Shakuntala, with Dushyanta riding into the ashram to encounter the dazzling damsel (the famous Raja Ravi Varma pose is elegantly referenced in one of the dance poses).
the music, the playback
A.R.Rahman tuned an exquisite Carnatic classical based song for 'Narumugaiye' using the traditional mridangam, ghaTam, violins and veeNai (if I recognise it correctly). (It would surprise some who saw him merely as a pop musician.) The song blends in wonderfully with the visuals and the lyrics, and is one of the great melodies of the Rahman catalogue.
The choice of the playback singers was particularly of interest. Unnikrishnan and Bombay Jayashri, both classical singers of some repute, gave their voices to this song. Unnikrishnan had already made a stunning debut (for Rahman), winning a National Award for "ennavaLe" (Kadhalan) and "uyirum niiye" (Pavithra) a couple of years ago. Bombay Jayashri was the bigger surprise packet - she was well-known in the Carnatic music circuit for a while for being one of the best singers from the younger generation, and this was a big step in terms of more commercial fame (of course, she became much more famous for 'Vaseegara' (Minnale)).
In the early days of TFM, the participation of classical singers in playback was a fairly common occurrence, for after all, they were the experts. The likes of M.S.Subbulakshmi (famously, an actress too) and M.L.Vasanthakumari (whose daughter Srividya would later join films) were associated with several big numbers. The parting of ways and the snobbery associated against film music would happen later given the nature of the productions (though in recent times, we have seen more practising Carnatic singers take to the mike for non-classical times in a long time - of course, K.J.Yesudas was a different phenomenon). The songs of that point were heavily influenced by the classical tradition, which is why the choice of the playback singers for this song was so relevant.
Vairamuthu's lyrics invoked the now highly abstruse classical (Sangam) Tamil, in which much of the great classics of Tamil literature were written. It's far removed from the common forms of Tamil these days, which makes it hard for people like me with no formal schooling in Tamil to follow. Vairamuthu made some direct references to some of the great works, using phrases from them and thus evoking the classic age. The result was a very fine marriage between words, visuals and music.
Madhubala showing off her bharatanatyam skills as the fragile Shakuntala watched by the warrior Dushyanta, surrounded by deer, waterfalls and such mytho-historical knick-knacks forms the "movie" side of the song. This is shot in Black and White with the old-fashioned stylistic dissolves and spiral wipes that establish the "period" of the visuals very well. The real-life romance is in colour, in much more plebian surroundings with the smitten Anandan illustrating to his bride some of the movie action - a contrast that is great to watch and is excellent for character development. Santosh Sivan's camera begins to have a dynamism of its own in these songs.
Useful web references
1. A post on Naadodi that gives some literary context to the lines "aTTrrai thi.ngaL avveNNilavil"
2. A typically passionate TFM forum discussion on bringing literature to the common man via film songs
3. Another TFM forum thread about the merits of Vairamuthu's references
4. Lyrics of the song (in Tamil only, untranslated)
5. Lyrics with English translation
6. Bombay Jayashri's website
7. Unnikrishnan bio