My theory -they got home from judges houses, and started editing and noticed a member of production team walking past window during a song. Didn't gave time to reshoot so made up ghost story????

It was Steve Brookstein

Lol the conspiracies continue! Simon pointed out while Anton was talking that he saw a ghost so that theory is incorrect anyway..

Omg legit crying

Did you notice Simon looking toward the left first and then looking forward and mentioning the 'ghost'? Almost as if he was waiting for a cue. Also, why would he think it was a ghost? :/

Thought it was Louis

By the view from the window they were not on the ground floor so how could a random person be just passing the window

Because it wasn't a random person, it was a ghost!
Simon said tw house is haunted so it isn't unusual that a ghost would appear.

trying to take us for mugs again (ROLLEYES) a 'ghost' ?! my @$$, it wasn't even see through (ROLLEYES)

I wouldnt be surprised if someone was winding Simon up all day about it being haunted he's a bit renowned for being gullible with those sort of things.