Also known as Krishnakumar Kunnath, the singer passed away at the age of 53 shortly after performing live in a concert in Kolkata, West Bengal on May 31.
His songs reflected a wide range of emotions and struck a chord with people of all age groups.
Reportedly, the singer fell sick while performing at Nazrul Manch in Kolkata.
He was reportedly rushed to a private hospital where he was pronounced dead.
The singer is now survived by his wife Jyothy Lakshmi Krishna and two children.
The singer got married to his childhood sweetheart in the year 1991.
Prime Minister Narendra Modi also expressed his condolences over KK's untimely demise.