KSI

Olajide Olayinka Williams "JJ" Olatunji (born 19 June 1993 in Watford, Hertfordshire, England), also known as KSIOlajideBT or simply KSI, is a YouTube and Internet celebrity, comedian, musician, video game commentator, and judge on the British talent show Britain’s Got Talent. He has a younger brother named Deji who creates and produces similar content on YouTube. Olatunji is known for his crude, and often sexual, humor. He was a guest judge on Britain’s Got Talent for the 2025 season as Bruno Tonioli had to miss a few auditions due to filming conflicts, and Simon Cowell took a few audition days off due to Liam Payne’s death. He then was announced that he would be returning to Britain’s Got Talent in 2026 as a full time judge, replacing Bruno Tonioli due to his commitment to the American Strictly Come Dancing, Dancing with the stars. He is also a member of the British YouTuber group, the Sidemen, which he formed on 19 October 2013 along with YouTubers Vikram Barn (Vikkstar123), Josh Bradley (Zerkaa), Tobi Brown (TBJZL), Simon Minter (Miniminter), and Ethan Payne (Behzinga); they were later joined by Harry Lewis (Wroetoshaw) in 2014.