A beautiful gown and the best way to repair rip Camilla gown is to use the french seam method.  Rip is in the front at the armhole in a very noticeable position.  This very short video shows how Judith repairs the rip so that it is almost impossible to see where it was torn.

Before doing this repair, unpick the hem allowance on the edge of the armhole.  Always do this before starting any repair, so that once the rip is repaired, the hem allowances will be turned back and stitched.

Creating a french seam involves place wrong sides together first, bringing the two sections together.  Use Duckbill scissors to cut away the fray.  Iron the seam and turn placing the seam at the edge.  Stitch as close as possible to the encased seam.  Press seam.