"Guinevere wears this burgundy red gown briefly in the middle of the film, King Arthur. It has a tie belt of the same material as the dress, which looks like it is attached to the gown. It has a tight bodice, possibly a corset. It looks like there is an inset at the `v` of the neck, as can be seen in the first picture. Interestingly in the exhibit photograph, the in set is higher, appearing to be attached to a previously hidden white section. Perhaps a slip underneath to protect her modesty?
The neck is a squarish `v` which hangs on her shoulders. There is a dull gold trim with red detail, and also some green. The sleeves are gathered to allow her hands out of them. There is an undersleeve, obvious in the second picture. It is gold to match the neck trim and is tight. The outer sleeves are huge. The fabric looks to be wool with a houndstooth pattern of burgundy and black. " (http://www.costumersguide.com/kingarthur2.shtml)
This may be two dresses instead of one. There may be an underdress as well as the red overdress. The small inset in the neck and her undersleeves are a good indication that there is a separate dress underneath.



The dress is a pale blue/silver crushed velvet (probably panné), done over in gold leaf in a widespread arching diamond scallop and swirling design, with what looks like sprigs of berries. Down the center are eleven false buttons, gold and round (not set on a seam).
The neck is scooped, with a one to one-and-half inch band of trim in the same fabric as the sleeves. This is edged in the self-fabric corded piping. Embroidered on the trim are close set yellow gold flowers, with a bead each for the centers.
The dress is seamed in a similar way to her Green Archery dress: a center front piece, and princess seams that end not at the top shoulder seam but curve over to the sleeve. Also, no standard center side seam. Instead, there is one direct side piece, allowing better for a fitted waist and a wide skirt.
We don't know how the gown closes in the back.
Sleeves
The blue satin sleeves are probably silk. There's an upper and a lower sleeve: a short sleeve ending in a band of trim, then lower sleeves. It seems that the upper and lower are separate; often there's a gap between the trim and lower sleeve, and folds of silk under it.
Where the lower sleeve attaches is the question. Is it a separate underdress? If it follows the basic idea of Peter's and Edmund's outfits it's plausible. But we're not seeing it anywhere else except the lower sleeve. The likely option is that it's attached at the armhole, or even at the top edge of the trim.
The lower sleeves are large bells that cascade beautifully around her hands. The top hem falls at her wrist, but the bottom of the sleeve extends at least a foot below her fingertips with her arms hanging down.
Images suggest the sleeves are finished with a very slender self-fabric binding. If not, it could be just a narrow rolled hem.
Note that in the exhibit images the sleeves appear a much paler, lighter blue than in the film and other images.
The two inch trim at the hem of the upper sleeve is simply a band of the same fabric as the sleeves. Segueing the top sleeve to the bottom sleeve, it's either finely topstitched about 1/4" from the top and bottom or lined with itself, with piping in the seam.
The band is embroidered in the same gold flowers as at the neck, all about the arm trim. The embroidery is embellished with trails of beads.
Thanks to The Wardrobe Door ( http://costumes.narniaweb.com/sucoronation.asp)
I was thrilled when I heard that The Chronicles of Narnia was being made into a movie. So thrilled that I decided I would dress up in costume to go see it! Months before I was busy planning and sewing. This is the product of my labor.
The Bodice/Skirt is made of light blue crushed penne. The Sleeves of darker blue satin.

The trim on the sleeves and the neckline is a beautiful blue and gold that, although they don't exactly match the gown in the movie, cordinate wonderfully with the rest of the dress.

it laces up the back,

And 11 buttons down the front for decoration.

The Gown:
The skirt and bodice look to be made of a solid fabric, possibly a silk or chiffon. The front of the bodice and the lower edging is heavily embroidered and beaded. It also has the basic corset shape with a solid front piece and at least four side pieces and two back. The neckline is a low cut square shape. The skirt is full and probably has the traditional bumroll as the skirts don't seem to have the structure a farthingdale would lend. The embroidery on the bodice continues down the front off the skirt. The sleeves are straight downt to the elbows where they are gathered up and adorned with lace.
The Veil:
The veil is a sheer fabric that is possibly around eight to ten feet long. It looks to be fixed to a flower wreath that is placed on the head.

[Thanks to Maggie from The Costumer's guide for the pics]