So this is how I made the dress from the film King Arthur.
I am no seamstress I merely made this in a methodical way.
Anyway, with all of that aside I hope this helps or at least sheds some light upon how to make it.
After step 5 please turn inside out to hide the seams, for the sleeves you will see the seams anyway unless you make them separately.
I used around 3 meters of fabric that was 60 inches wide.
The cotton jersey fabric was a soft stretchy type so it draped really well.
I have some new photos of the dress here [link]
and here [link]