Nicolai Kielstrup (born 4 October 1991) is a Danish singer who participated in the Junior Eurovision Song Contest 2005.
Kielstrup was born in Vejle, Jutland. In 2003, he was present at the Junior Eurovision Song Contest in Copenhagen, as he knew one of the participants.
In 2004, he wrote "Shake, Shake, Shake", a rap song about a nervous boy who falls in love after meeting a girl on the bus on a school field trip to a pond. He performed it at the MGP Junior 2005 scoring maximum points. His resulting participation in Junior Eurovision 2005 earned him a fourth-place finish.