Catherine Middleton, Duchess of Cambridge, and Grace Kelly, Princess of Monaco. Photos: Getty Images

When Grace Kelly married Prince Ranier III of Monaco in 1956 she wore a white lace dress designed by Helen Rose, MGM’s award winning costume designer. Rose, and a team of thirty-six seamstresses, spent six weeks on the gown. Sarah Burton’s spent months on Catherine Middleton’s white lace gown—and given the secrecy under which she had to work we imagine Burton employed far less people. The results are startlingly similar, down to their bouquets, tiaras and veils. So in case you end up marrying a prince, take note: lace sleeves are a royal must!