When it comes to FIFA World Cup uniforms, every centimeter has to be followed to a tee, including their underwear
It's not an uncommon sight, especially for those who follow football matches religiously.
But why do players practise this "mischievous" stunt?
The reason is pretty simple.
Officials apparently check the footballers' underwear (if they wear any at all) to make sure that it's the same colour as their shorts.
According to Western Journal, "FIFA's rule, adopted by most of its member associations for club soccer, is there to prevent the players from using their undergarments to display messages that may not be FIFA approved."
National Football League (NFL) also followed a similar rule for decades.
Back in Euro 2012, Danish player Nicklas Bendtner was given a hefty fine of GBP80,000 (RM422,000) for exposing his 'wrong' coloured underwear
He managed to get away with it when the underwear company Paddy Power picked up his bill for him.
Following that reasoning, the rule seems pretty sensible but it's unclear as to what happens if an official catches a player breaking the rule before a game.
Would he be sent back to change quickly? Making him skip the match completely seems pretty intense.
But it has happened before.
In 2011, Bath City Football Club (FC) had two players knocked off the FC Youth Cup match for wearing mismatched underpants and shorts
Apparently, officials had failed to check them prior to the match and the boys were told by the referee to change during the game.
The Bath City chairwoman felt that it blew out of proportion when the players had to go to the side of the pitch, strip down, and change in front of everyone.
"I would have hoped someone would have thought the purpose behind this rule isn't to make a 16-year-old strip in front of a crowd," she said, according to BBC.