I was listening to the song Nila Kaigirathu from the movie Indira (1995) a few days back, and I felt that a portion of the pallavi (refrain) was very similar to the one in Kaadhal Piriyaamal from the movie Panchatanthiram (2002). A. R. Rahman is the music director for the former movie and Deva for the latter.
Nila Kaigirathu
• Listen to the portion from 0:59 to 1:08 in the female vocals version or from 0:56 to 1:05 in the male vocals version, and
Kadhal Piriyamal
• Compare with the portion from 0:18 to 0:27.
Is there any information about whether Deva took inspiration from A. R. Rahman's earlier work when composing this song (maybe in some interview with the music directors, etc.)?
Interestingly, the Wikipedia article on Panchatanthiram says the following (in the section titled Production):
[T]he team initially planned a film starring Kamal Haasan with music composed by A. R. Rahman. Though recordings had taken place, Thenappan became apprehensive of the budget and chose to make a smaller budget film, meaning Deva replaced Rahman.
Source: Wikipedia contributors. Production. In Panchatanthiram. Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Panchatanthiram&oldid=959011166#Production, 2020-05-26. Accessed: 2020-06-01.
My idle speculation is that A. R. Rahman could have used one of his old songs as an inspiration for a basic outline, and Deva could have developed one of these tunes that Rahman left behind into a full-fledged song as Kaadhal Piriyaamal, but of course I have no evidence to back this up.