Olajide Olayinka Williams "JJ" Olatunji ( born 19 June 1993), known professionally as KSI, is a British influencer, musician, and former professional boxer. He is a co-founding member of YouTube group the Sidemen, the co-founder of Misfits Boxing and co-owner of several businesses, including Prime Hydration and Lunchly. KSI has also served as a judge on Britain's Got Talent since 2026. Born in London to parents of Yoruba heritage and raised in Watford, KSI was privately educated at Berkhamsted School. He registered his main YouTube channel KSI—then known as KSIOlajidebt—in 2009 and built a following through his commentary videos of the FIFA video game series. His content later diversified to include vlogs and comedic skits. In 2019, he was ranked second by The Sunday Times in its list of most influential online creators in the United Kingdom. In 2021, he was listed in the Europe Entertainment category of Forbes 30 Under 30; he was later ranked by Forbes as the second-top creator of 2023. As of January 2025, he has over 44 million subscribers and 14 billion video views across his three active YouTube channels. Creating hip-hop music as early as 2011, he first achieved commercial success with "Lamborghini" (featuring P Money) in 2015. His debut EP, Keep Up (2016), topped the UK R&B Albums Chart. He released his debut studio album, Dissimulation, in 2020, which peaked at number two on the UK Albums Chart. His second studio album, All Over the Place (2021), debuted at number one...