This is the Reiss “Nanette” dress. The ivory dress features a frill along the front zip extending from the neckline to the hip. It has a tulip skirt and 3/4 length sleeves.
It is a lovely dress but it is a bit short for royalty.
1) Kate wore it for her engagement portrait taken on 25th November 2010 at St James Palace
2) The dress was worn again for Canada Day on 1st July 2011, Ottawa, Canada. It was accessorized with a hat by her favourite milliner Sylvia Fletcher at Lock & Co, featuring Canada’s national symbol, the maple leaf, red shoes and a diamond brooch, which was borrowed from the Queen.