IN PICS: Kate Middleton turns 30!

As the Duchess of Cambridge brings in the big three-oh in 'a low-key and private' affair, we take you through the life of the girl who would become a princess.

Kate Middleton is all set to celebrate her 30th birthday in a quiet ceremony. The Duchess of Cambridge was last spotted at the premiere of Steven Spielberg's latest movie War Horse with Prince William in London after which she would settle for celebration that the palace officials describe as 'a low-key and private affair'.

We take you through the life of Kate Middleton from the time she was three to the day she became the Duchess of Cambridge.

Here she is, emerging from the shadows, much before she became the Duchess. The picture shot at St Andrews, Scotland -- the university where they first met to launch a fundraising campaign for a new GBP 13 million scholarship and students support.

In this handout image provided by Clarence House, Kate Middleton is pictured aged three on a family holiday in the Lake District.

The little princess? In this Handout Image provided by Clarence House, Kate Middleton is pictured aged five.

In yet another handout image provided by Clarence House, Kate Middleton is seen with sister Pippa and father Michael in Jerash, Jordan. The Middleton family had moved to Amman, Jordan for two and a half years before finally settling in England.

Kate Middleton and Prince William have dated on and off for over a decade. The two met at St Andrew's University in Scotland from where they graduated. This picture has been taken on the day of their graduation ceremony on June 23, 2005.

Always aware of the watchful eyes of the press, Kate Middleton has almost always been well turned out -- long before William popped the question. In this picture from March 2008, Kate Middleton makes a fashion statement with a stylish hat at the David Nicholson Mares Hurdle at Cheltenham Racecourse.

And it's official! The will-he-won't-he question was finally answered in the winter of 2010 when Prince William proposed marriage to Kate Middleton. The couple, who got engaged during a holiday in Kenya, pose for photographs in the State Apartments of St James Palace in London.

Can't believe it? Middleton looks at her ring that was once worn by Princess Diana and was meant to be worn by the girl who won the Prince's heart.

Never the one to lose the common touch, Kate Middleton reaches out to the crowd, weeks before her high-profile wedding to Prince William.

Constant comparison with Princess Diana is something Kate Middleton must live with. It's probably safe to say that the Duchess of Cambridge has been doing a great job at it so far. Not only is she matching up to her late mother-in-law in style, she has also been engaged in various charities like Diana.

A lesson from the princess to brides-to-be? Much unlike many soon-to-be-married girls Kate Middleton looks cool as a cucumber as she arrives at The Goring Hotel after visiting Westminster Abbey less than 24 hours before her wedding. Sure, she's had a hundred people taking care of the arrangements but then again, it was the wedding of the century, wasn't it?

All smiles, Kate Middleton readies herself for the much-awaited for the walk down the aisle on April 29, 2011 with her sister Pippa. According to the New York Times, the wedding was watched by three billion people across the world.

Ever since the death of Princess Diana, the British public have longed for a royal couple they could look up to. Even though Prince Charles married Camilla after being divorced, the Duchess of Cornwall never really could fill the shoes left vacant by the People's Princess.

In a sense, Prince William and Kate Middleton's kiss on the balcony of Buckingham Palace brought back memories from Princess Diana's wedding and became a moment that that would be cherished by this generation of Britons.