I'm starting a new file, because I'm assuming I need to in order to access the DLC, as is custom for Dark Souls. I realize the DLC has only been out for an hour at this point, but I'm curious as to at what point of the game I'll be able to access Ashes of Ariandel. If anyone finds out, please tell me, but use spoiler tags for specifics, as I'd like to find out where it is at least sort of on my own!
Seems to be accessed by a location at the Cathedral of the Deep zone. You can read the article for more details.
Based on the article's information, it seems like starting a new game was not the way to access this DLC, since this area is not available at the start.