Kate Middleton Style: How The Duchess Echoes Jackie O, Princess Diana and Audrey Hepburn [PHOTOS]

Jackie O. Princess Diana. Audrey Hepburn. These three women were not only fashion icons, but they were also trendsetters for entire generations. Of course, there is more to being a trendsetter than just being stylish. It takes a certain aura, a certain mystique and (most importantly) a certain type of person to reach that level.

Kate Middleton has reached that level.

Kate Middleton might have been deemed the girlfriend of Prince William before the Royal Wedding. But come April 29, 2011, when Middleton glided down the aisle of Westminster Abbey, everything changed. Middleton became a Duchess and the world became enthralled.

Since that fine day just one year ago, the brunette beauty has basked in an adoring spotlight that very few celebrities have the pleasure of experiencing. It is not just her royal status, her fabulous wardrobe or her effortless style. Kate Middleton exudes a collected, calming confidence and a beautiful poise that cannot be taught.

Here is how the Duchess of Cambridge echoes an influence akin to some of the most famous style icons who preceded her.

She Sticks to the Classics

Jackie O became a fashion icon when in the fall of 1960 she had Oleg Cassini design an original wardrobe for her role as First Lady. Matching skirt suits, sleeveless A-line dresses, kitten heels, elbow-gloves and pillbox hats came to symbolize the Jackie O look. Though her style evolved as time went on, Jackie stuck to the classics. She remained true to herself despite the countless fads that sprung up around her.

Similarly, Kate Middleton adheres to a classic style that will never go out of vogue. Matching suits, elegant hats, slim-fitting pants, lace overlays and pumps make Middleton's wardrobe something of timelessness. One of her favorite staples is the L.K. Bennett pump. Middleton opts for this classic footwear with everything from a dazzling gown to a simple sheath dress. It is important to have those classic essentials to anchor your wardrobe. They will define who are you and who you present yourself as.

A Pleasing Palette

Diana Spencer entered the British royal family in 1981 and became a princess. Princess Diana, who was ranked in TIME's All-TIME 100 Fashion Icons, might night have been born a noble, but she certainly knew how to dress like one. Reflecting her personality, she made laidback look elegant, and transformed the traditional regal look into something altogether more inviting and modern. She loved color - from sparkling cabbage to crimson to orange - and materials from taffeta to lace, wrote TIME's Jayne Fincher.

Kate Middleton's color palette is just as eye-catching. The Duchess consistently flaunts jewel tones like sapphire, ruby, amethyst and emerald. After Middleton stepped out in a pair of coral jeans to greet the UK's Olympic field hockey team, sales of Asda's colored denim shot up 88 percent, according to England's Daily Express. Choose colors that not only complement your coloring, but that also say something. If you are outgoing and boisterous, loud neon colors will suit you; if you are genteel and mellow, pastels are your perfect match.

Easy Breezy

Audrey Hepburn's style was so beloved because it was easy; it was a style the everyday-woman could adopt without much muss or fuss. Her relationship with Hubert de Givenchy helped develop this. [Givenchy] gave me a look, a kind, a silhouette. He has always been the best and he stayed the best. Because he kept the spare style that I love. What is more beautiful than a simple sheath made an extraordinary way in a special fabric, and just two earrings? said Hepburn. A little black dress, a pearl necklace and some oversize sunglasses were all she needed.

Kate Middleton keeps her style just as easy and that is what makes the Duchess so lovable. Although she has the Crown Jewels at her disposal, Middleton instead opts for styles from H&M, Harrod's and TopShop. On the weekends, you will see her in jeans and loafers. Do not get too caught up in looking perfect all the time. The best looks come the easiest. Simple straight leg pants, a striped sweater, ballet flats and a swipe of red lipstick can work wonders.

Most of all, Kate Middleton is relatable; and that is something that we can all admire.

Here are some of Kate Middleton's best style moments.