A cheap zip-up hoody from Primark, removed zip and stitched the sides together from the inside leaving a deep V-neckline.
The eyelets I salvaged from an old corset top (the plastic boning had warped hideously!) which I pinned and sewed on, though equally you could punch holes and fit eyelets straight into the top.
I made a bit of a sloppy job on this one, at some point I'll get round to neatening it up and improving the fit. It is very cosy afterall.
Cute Halloween costume that will probably work it's way into regular wardrobe rotation!