Olajide Olayinka Williams "JJ" Olatunji (/ɒləˈdʒiːdeɪ ɒləˈtundʒiː/, oh-lah-JEE-day oh-lah-TUHN-jee; born 19 June 1993), better known as KSI, is an English YouTuber and rapper.[8] He is a co-founder and member of the British YouTube group known as the Sidemen.[9] He is also the co-owner of Prime Hydration, XIX Vodka and a restaurant chain known as Sides.[10][11]