minhag - Why do some men wear the kitul under their suit jacket at their wedding?

I'm not sure if there is any halachic basis for any of this, but I've seen at most weddings the chasan just wears the kitul over the suit jacket. At a few weddings though, particularly in Israel, many chasanim wear the kitul underneath their jacket. Any reason for this?

Answer

A friend of mine was told by his rebbe at Chofetz Chaim yeshiva in Queens that it's a personal Yom Kippur -- hence, wear the kittel, but not out in the open.