Oru Kal Oru Kannadi sees Udhayanidhi Stalin as Saravanan and Hansika as his love interest Meera. The film has Santhanam playing a comic role as Parthasarathy.

Director Rajesh M explaining about the characters in the movie says, “Saravanan is the ticketing incharge in a theater and Santhanam works in the canteen of the same theater.” He further added, “How these three meet and how love blossoms between the lead pair forms the crux of OKOK.”

Rajesh said, “Udhay and Hansika chemistry was good on screens and Santhanam’s comedy sequences went good.” The director, who has Santhanam in all his films concluded, “I can make movie without a heroine, but can’t film it without Santhanam.”