Krishna Kumar (also known as K.K./Kay Kay) is an award winning Indian playback singer. He is a prominent singer in Hindi, Tamil, and Telugu films.

He got his first break when he got a call to sing a one-minute jingle for Leslie Lewis for UTV, which kick-started his career. His first song for Bollywood film was Chhod Aaye Hum (Maachis). But it was the song Tadap Tadap, from the movie Hum Dil De Chuke Sanam, that brought him into limelight.

Although, a new singer, his distinctly clear voice and excellent throw has made him Pritam, Vishal-Shekhar and other music director's favorite.
He has also sung in South Indian languages - Tamil and Telugu. On January 24 2008, KK's second album Humsafar was released.