Kamal Hassan and Raghuvaran were going to act with each other in Mani Ratnam's Nayagan. The role of the Assistant Commissioner was given initially to Raghuvaran. However later Raghuvaran couldnt play the role and the role eventually went to Nasser.
Raghuvaran had unfortunately injured himself which made him not play the role and the role eventually went to Nasser.
A widely popular reason which people say is that Kamal Hassan was intimidated by Raghuvaran's Talent and Dedication for each role and performance.
He couldn't digest the fact on how Raghuvaran may be miles better than him as an actor and dedicated performer.
However This is just some theory because Kamal Hassan hasn't had that much personal hate and ego on Raghuvaran and there's not much evidence to prove whether Kamal Hassan actually felt threatened and intimidated by Raghuvaran and his acting.
The true reason why Raghuvaran couldnt play in Nayagan was because he unfortunately injured himself which made him not play the role and the role eventually went to Nasser.
Later Raghuvaran and Kamal Hassan went in different paths with Raghuvaran focusing more on Villainous / Character roles and Kamal Focusing more on comedies.
Hence there wasn't much room for a potential collaboration. It would have been great to see both the actors on the big screen together but unfortunately that couldnt happen.
Do tell your opinions in the comments below. Till then this is Krish Ranjan signing off!!!