The actor can currently be seen in the psychological thriller Special Chabbis.
He told The Times of India: "I'm accustomed to commercial success but not critical acclaim - I am used to rewards and not awards. I am getting recognition, and that too from critics who had never written one good word about any of my performances till this film happened.
"This film has given me a chance to rediscover myself as an actor."
Kumar added: "For me, it was an opportunity to learn. Previously, whenever I had asked Anupam Kher and Paresh Rawal about their intermittent theatre stints, they would tell me that the process helps them reinvent themselves."
The actor revealed last week that he had turned down the role in Special Chabbis the first time he was offered it.
He recently recorded a song in character, dedicating the number to "Valentine's Day lovers".
Watch the trailer for Special Chabbis below: