Simon Cowell missed the America's Got Talent season 21 finale on Sept. 22 while recovering at home from back surgery. The executive producer sent finalists his support in a message read by host Terry Crews during the first night of the supersized finale. Cowell said he was disappointed to miss the broadcast in person but planned to watch from home. The 66 year old has been absent from several episodes after undergoing a routine procedure connected to injuries from a 2020 biking accident that damaged multiple parts of his back. Who Filled Simon's Seat? KSI temporarily joined the judging panel alongside Howie Mandel , Sofía Vergara and Mel B as the show prepared to crown its season 21 winner. Cowell also managed to slip in a characteristically cheeky warning about KSI staying hydrated around Mel B. Howie Mandel shared on Sept. 3 that Cowell's operation had been successful and said the Britain's Got Talent creator was eager to reconnect once he felt better. Terry Crews also acknowledged that the finale felt different without Cowell, but KSI brought influencer, musician and professional boxing credentials to the temporary judging gig.