At the Karnan press meet event that took place on Wednesday, film's director Mari Selvaraj revealed how he came to collaborate with Dhanush. The director revealed that his first movie, the critically acclaimed Pariyerum Perumal (2018) was written for Dhanush.

This doesn't come as a big surprise given how back in 2019, Dhanush had publicly expressed his disappointment over Pariyerum Perumal not getting recognized at the National Film Awards, that year. 

Mari Selvaraj also said that he writes all his films for Dhanush, so when the actor called upon him to ask for a story, the director was ready. He also revealed that 30 minutes into the meeting between him and Dhanush, everything fell in place for Karnan.