Here is waht the director of the upcoming H & K go 2 amsterdam MOVIE said in a new press release

" We decided that they want Neil Patrick Harris to come back for it.

". I think it will be great... Neil eatinh shrooms and smokin herb with Harold & Kumar in a coffeshop" he says, "the movieā??s going to be called Harold and Kumar go to Amsterdam, so we have him pop up over there".