Kate Middleton wore this Roksanda Illinic Peridot dress in lavender when arriving in America back in July. Original retail price was $1240 at Net-A-Porter (sold out).
If you love this look, check out this affordable lookalike from Adrianna Papell. It retails for $98 and will give you a royal look for a lot less cash. Click on the photo below if you're interested in purchasing.