Kassidy were a Scottish alternative folk rock band. The band consisted of Barrie-James O'Neill (vocals and guitar), Hamish Fingland (vocals and guitar), Lewis Andrew (vocals, guitar, accordion and keyboard) and Chris Potter (vocals and guitar). The band was formed in late 2009 in Glasgow.
The quartet met through friends' bands and fortunate pub encounters. Kassidy began writing and recording their music in a share house, which they later converted to a personal studio. They released three EP's, the second entitled The Rubbergum EP Volume 2 on 16 August 2010.
They released their second album One Man Army on 30 April 2012.
The band toured along with Lana Del Rey from 3 April 2013 to 31 May 2013 on her Paradise Tour in Europe. The same year, the frontman Barrie-James O'Neill collaborated with Del Rey on a cover of "Summer Wine" originally composed by Lee Hazlewood, and appeared in its music video with Del Rey.
On 8 April 2013 the band released their EP album called People Like Me on iTunes.
On 1 February 2014, the founder and frontman of the band, Barrie-James O'Neill, left the band to move to Los Angeles to be with his then girlfriend, Lana Del Rey, and has since adopted the stage name "NiGHTMARE BOY" as a solo artist. He has released two singles and an EP under NiGHTMARE BOY. The band continued for a short while but split later that year. The remaining members have since formed a new band called White along with Leo Condie and Kirstin Lynn.