This will make Arsenal and Tottenham fans feel uncomfortable...
Football and fashion do not always go hand in hand - but this is a big a no-no as you could find.
A photo has been posted online of a lad out wearing a Tottenham Hotspur shirt - accompanied by Arsenal shorts.
The two clubs are bitter rivals and the faux pas even caught the attention of former Arsenal striker Ian Wright, who responded on Twitter accordingly...
Whether there is a story behind the photo is unclear... but really, there is no excuse surely.
Arsenal and Tottenham - A recent recap
Perhaps the biggest controversy between the two clubs happened over a decade ago when Sol Campbell ditched Tottenham to sign with Arsenal on a free transfer.
The deal saw him labelled a Judas by fans, who had to watch him go onto win numerous trophies with Arsenal.
Tottenham fought back around 2010, going onto qualify for Champions League football and mount a consistent threat to Arsenal's place in the top four, but have yet to finish above their rivals since Arsene Wenger took charge, and have slipped back since.
Just this summer Arsenal star Jack Wilshere was disciplined by the FA for mocking Spurs during the club's FA Cup winning parade.