Bald co-worker

Kind of a sensitive one here, if a co-worker wore a wig and it was a good one and no one knew he was bald.
Then some people at work found out and you know what happens next right? Everyone knows. There are around 120
of us, but due to the nature of the work we work in groups not on site. Would you just ignore it or say something
to them about their wig? I mean the guy is as bald as an eagle.