Lady Diana Spencer was just 19 years old when she became engaged to Prince Charles, heir to the British throne. And although the blue-eyed blonde would become an international style icon, she committed some fashion faux pas in the beginning. The blue suit she wore at the engagement announcement, for example, was downright frumpy. And in one of her first formal appearances, in March 1981, she caused a sensation by wearing a strapless black dress to a gala. Royals don't wear black, except for mourning, and they definitely do not show so much cleavage.
But despite some early gaffes, the constraints of having to dress conservatively (remember all those big hats?) and the unfortunate fads of the 1980s, Diana still managed to make everything she wore look good.
Royal Fashion: Diana and Kate
As she became more confident in her role, the princess developed her own sense of style, with some help from favorite designer Catherine Walker. In her 30s, especially after her separation from Charles, Diana became more daring, wearing her shorter skirts and adopting a much sleeker look to show off her figure.
Middleton, on the other hand, has never put a foot wrong since she first appeared on the scene. After an early appearance at a student fashion show, where she modeled a sheer dress over a black bandeau top and bikini bottoms, she has never been accused of showing too much skin.
William, Kate Get Engaged
Who Is Kate Middleton?
The Man Who Could Be King
Engagement Announced on Twitter
William and Kate Photos
Kate Middleton's Engagement Ring
10 Questions on the Wedding
Royal Style: How Kate Compares
How Close Is Harry to the Altar?
Royal Engagement Souvenirs
More on Catherine Middleton
Royal Wedding Planning
Royal Wedding Photos
Even in her early 20s, she shied away from the wilder styles of the younger set. Instead, she developed an elegant, ladylike style. One of her favorite labels is Issa, by Brazilian designer Daniella Helayel.
Of the few criticisms Middleton has had to face: She sometimes dresses old for her age, and she has worn a favorite pair of black boots a little too often.
Now speculation centers on who will design Middleton's wedding dress -- and here, she hopefully will learn from her predecessor's mistake. Diana's ivory silk wedding dress, by David and Elizabeth Emanuel, seemed the stuff of fairy tales from a distance, but it didn't wear well. With a train that stretched 25 feet, the poufy gown barely fit into the glass coach that carried Diana and her father to St. Paul's Cathedral, and its billowing folds all but swallowed the bride.