The former England captain and coach passed away at the age of 75 on Monday (20.07.26) - six months after revealing that he had been diagnosed with stomach cancer - and the Prince of Wales, who serves as patron of the Football Association (FA), has paid tribute to an icon of the English game.
William wrote on social media: "Incredibly saddened to hear of the passing of Kevin Keegan.
"A truly remarkable footballer and manager who inspired generations with his talent, passion and love of the game.
"Above all, he will be remembered as a kind and generous man.
"Our thoughts are with his family and all who knew him."
Keegan started his career at Scunthorpe in the 1960s before joining Liverpool in 1971 - where he won three First Division titles, the FA Cup and European Cup and established himself as an England international.
The forward played 63 times for England between 1972 and 1982, scoring 21 goals and captaining the Three Lions at Euro 1980.
He then moved to German club Hamburg in 1977 - winning the Bundesliga title in 1979 and claiming the prestigious Ballon d'Or award twice (the only British footballer to do so).
Keegan then returned to English football with spells at Southampton and Newcastle United before retiring as a player in 1984.
He would later return to the Magpies for a memorable spell as manager from 1992 to 1997, where he famously came close to leading Newcastle to Premier League glory in 1996 before his 'Entertainers' team were reeled in by Manchester United despite having had a 12-point advantage at the top of the table during the campaign.
Keegan managed England from 1999 to 2000 but resigned as Three Lions boss as they lost 1-0 to Germany in a World Cup qualifier that marked the final match played at the old Wembley Stadium.
He also had managerial spells at Fulham and Manchester City, before an unsuccessful return to Newcastle that lasted just eight months in 2008.
Magpies legend Alan Shearer - who Keegan signed for a then world record £15 million fee in 1996 - paid tribute to his "hero" on social media.
He wrote on X: "My Hero. My manager. My friend. Sleep easy Boss."
Former UK Prime Minister Sir Tony Blair, a Newcastle fan, expressed his sadness at Keegan's passing.
He said: "Kevin inspired everyone he met, including me. He was just a thoroughly decent man with a strong sense of values and a belief, not only in the game of football, but also in Britain as a nation.
"From the first time I met him in the Newcastle changing room before a match in the 1990s, to the time he took me in hand as the leader of the opposition to teach me how to head the ball, to the social occasions later in life he was the same: an effervescent, never-give-up, irrepressible proud patriot of Britain."
