Tyson Fury threatened to 'smack' a fan for singing '10 German Bombers'.
The chant was originally sung during World War II but has been adopted by English football fans in recent years.
It references German bombers being shot down by the RAF during the conflict.
And when Fury invited supporters to sing before a press conference, one began chanting.
But the former heavyweight champion said: "Shut your mouth or I'll smack it in".