His name is inextricably linked with both teams, club and country, and is recognised all around the globe as one of the greatest players to have graced the beautiful game.
Crucial to United's success in the 1960s, he is one of only two Englishmen to have won both the World Cup (in 1966) and the European Cup (in 1968) - the other being his Reds team-mate Nobby Stiles. His legendary manager at Old Trafford, Sir Matt Busby, once said: "The greatest thing for a manager is to trust the talent. Bobby Charlton never betrayed that trust. It was a privilege to have him play for you."
Now in the seventh decade of his association with United, Sir Bobby was, earlier this year, the ideal choice to carry the Olympic torch past the stadium he once famously nicknamed the "Theatre of Dreams".
That was a very special day for the club legend and ambassador, and today (Thursday) is another one. Happy 75th, Sir Bobby.