The England legend made 265 Premier League appearances for the Red Devils, scoring 61 top-flight goals as the midfielder won six titles during his Old Trafford career.
Beckham played in 81 Champions League games under Sir Alex Ferguson, and the midfielder played an important role in the club’s 2-1 victory over Bayern Munich at Camp Nou in 1999.
The Red Devils star, who also won two FA Cups, joined La Liga giants Real Madrid in a €35m deal in 2003, signing a four-year deal after he fell out with United boss Ferguson.
Beckham has since resolved his differences with the Scot legend, and the 40-year-old took to his Facebook page to reflect on the anniversary and upload a photo from his United days.
Beckham, who has made more England appearances than any other outfield player, retired from professional football in 2013 after a brief spell with Paris Saint-Germain.
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