This outfit is super cute, the fabric is super soft and a completely comfortable costume to wear; also fit me perfectly and not at all tightly fitted which is good because it is meant to be a nighty after all!! ( size small, height 5ft [152cm], weight 39kg. )
The hat of course will need to be bobby pinned to the wig if you want it to stay on your head, especially if you're doing alot of movement or if you want to take pictures laying down because it doesn't actually fit your head, especially with wearing a wig ( which makes it twice more cute ).
overall it's a great costume, 100% recommend getting.