KK was feeling unwell after reaching his hotel, following a performance at a concert in the evening where he sang for almost an hour, officials said.

He was taken to a private hospital in south Kolkata where doctors declared him brought dead, they said.

''It’s unfortunate that we could not treat him,'' a senior official of the hospital said.

KK, known as a versatile singer, has recorded songs in Hindi, Tamil, Telugu, Kannada, Malayalam, Marathi and Bengali, among other languages.