Barrie-James O'Neill (born 20 December 1987) is a Scottish singer and songwriter from Glasgow, Scotland.
O'Neill started songwriting at the age of 20.
On 1 February 2014, as the founder and frontman of the band Kassidy, O'Neill, left the band and moved to Los Angeles, he adopted the stage name "Nightmare Boy" as a solo artist.
He has released two singles and an EP.
On 8 April 2016, O'Neill released his debut album Cold Coffee, which included the official singles "Angel Tears", "Way Over My Head" and "Night Burns".
Barrie-James O'Neill is published by BMG Music Publishing worldwide.