Board Thread:Spoilers!/@comment-31231929-20170224180517/@comment-24674051-20170224200818

My guess is that "Song of my Heart" will be preparations for the Wedding (among other things), and given the mood, that is what is causing people to sing. (I've been known to break out into song randomly irl, so I have no problem with it happening on a TV show). 6x21 will be the wedding, and my hunch is that it is going to mirror what happened in the Pilot with Snow and David's wedding. (but the end of the wedding may be a bit different), and it is the wedding and what follows that leads to 6x22 and season 7.