Truly incredible scenes here as Billy Joe Saunders son punches and kicks US world title challenger Willie Monroe Jr on stage.

It’s hard to be surprised by anything after covering a sport as nutty as the fight business, but today’s weigh-ins in London could be a first.

WBO middleweight world champion Billy Joe Saunders and American based challenger for his belt Willie Monroe Jr both made weight for their fight today.

What happened afterwards was pretty unexpected.

Willie Monroe Jr could be seen putting his arm over Saunders’ son who was standing next to his father during the weigh in on stage when all of a sudden, the young man let fly on Monroe Jr:

(Hat tip IFL TV YouTube)

Surely a first for world title fights? Monroe no doubt will have his protective cup on hand going forward.

The pair are set to fight tomorrow night at London’s 02 Copperbox Arena for the WBO middleweight world title but also a chance for the winner to get a crack at the winner of Golovkin vs Canelo which takes place on the same night in Las Vegas.

The champion Billy Joe Saunders holds a pro record of 24-0-12KO while the challenger Willie Monroe Jr’s record stands at 21-2-6KO.