Ajax have been banned from wearing their original design for a Bob Marley-inspired kit by UEFA, which says the strip contained imagery that goes against the federation's rules.
The strip, inspired by the song Three Little Birds which has become an anthem for Ajax fans, was introduced for the 2021-22 season and was worn by Ajax for the first time in their Eredivisie victory away to PEC Zwolle on Saturday.
However, the shirt had been changed from the design initially revealed in the summer - and the reason has now been revealed as being down to an obscure rule from the European football governing body.
What has been changed?
Ajax wore the predominantly black kit with red, yellow and green trim, which is serving as their third strip for 2021-22, against PEC as their blue away jerseys resembled their opponents' home shirt too much.
The original kit had three birds stitched on the back, just below the collar - one in each of red, yellow and green - in homage to the Marley track. Eagle-eyed supporters soon realised during the 2-0 win on Saturday that the birds had been removed from the players' kits.
Asked by website Ajax Life for the reason, the club said: "The European Football Association [UEFA] sees it as a different expression than the club logo, logo clothing sponsor or sleeve sponsor. Other expressions are not allowed."
What is Ajax's connection to Bob Marley?
The kit, which was released in August and which Ajax will predominantly wear in European fixtures this season, with the Eredivisie side in the group stage of the Champions League, was inspired by the fans' association with the reggae classic, which started in August 2008.
Following a friendly away to Cardiff City, supporters were asked to remain in the stands after the game. Three Little Birds was one of the songs played by the stadium DJ and it quickly became adopted by Ajax fans as an anthem which is sung at every match.
The fan connection was made official by the club with the kit design this season, and has been welcomed by the family of Bob Marley.
His daughter Cedella Marley said: "I am beyond touched that Ajax has taken Three Little Birds and made it their anthem. Stories like this warm my heart and show how impactful songs like Three Little Birds can be. Soccer was everything to my father and to use his words, 'football is freedom'."