Dulé Hill reunites with his co-star, Bradley Whitford, on the latest episode of, and only ET exclusively debuts a sneak peek from their mini-reunion.On Wednesday's episode, titled «Bill's New Friend,» Whitford plays Alan Van Der Kamp, Dean's (EJ Williams) music teacher, who surprises Bill (Hill) with his extensive knowledge of the jazz music scene.In ET's exclusive clip, Bill enters Alan's band room with a bone to pick about his son's grade in his music class. The issue stirs up some confusion for Alan, who tells Bill he gave Dean an «A.»Apparently, the «A» is the problem.«Yes, and I think we both can agree he doesn't deserve that,» Bill tells him, «and his grade should be lowered.»«OK, this is a first,» an amused Alan replies.«I don't mean any disrespect.