On Air Now
The Smooth Late Show with Martin Collins 10pm - 1am
25 September 2018, 21:23
She's quickly become one of the most popular members of the Royal Family since her marriage to Prince William in 2011.
Here are the big facts about the future queen consort of the United Kingdom and the Commonwealth.
In 2001, Kate met William while they were both students at St Salvator's Hall at the University of St Andrews. She is said to have caught William's eye at a charity fashion show in 2002 when she appeared on the stage with a see-through lace dress.
The couple began dating in 2003, although their relationship wasn't announced. During their second year, they shared a flat with two other friends.
In April 2007, Prince William and Kate split up. They decided to break up during a holiday in the Swiss resort of Zermatt. However, a few months later they had been seen together and news sources claimed that they had "rekindled their relationship". For a while, her long-term relationship with William earned her the nickname "Waity Katie" in the tabloids.
On December 3 2012, St James's Palace announced that the Duchess was pregnant with her first child. The Duchess was admitted to St Mary's Hospital in London in the early stages of labour on the morning of July 22 2013, and gave birth to Prince George later that day.
The Duchess's second pregnancy was announced on September 8 2014. On May 2 2015, the Duchess gave birth to Princess Charlotte.
Her third pregnancy was announced on September 4 2017. Prince Louis was born on April 23 2018.
Kate Middleton was born on January 9, 1982.
She celebrated her 36th birthday in 2018.
According to regal rules, the wife of a King does have the title of queen, but they're not exactly the Queen of the country.
The name is purely a ceremonial title, just like how the Queen Mother was known as the Queen before her husband died.
English designer Sarah Burton, the creative director of luxury fashion house Alexander McQueen, designed Kate Middleton's bridal gown.
The dress and its maker were not formally announced until the bride stepped from her car to enter Westminster Abbey just before the wedding on April 29, 2011.
Kate's wedding ring of Catherine is made from Welsh gold. It was created by the royal warrant holder Wartski, a company with roots in Bangor, north Wales. Since 1923, it has been a royal tradition to use Welsh gold for the wedding ring of the bride.
The ring was made from a small amount of gold that had been kept in the royal vaults since it was given to Queen Elizabeth II. It was mined from the Clogau Gold Mine in the mountains of North Wales.
The Queen had "given a piece of the gold that has been in the family for many years to Prince William as a gift," a palace source said. Prince William chose not to receive a wedding ring at the ceremony.
William also gave Kate the same engagement ring that his father had given to William's mother, Diana, Princess of Wales — an 18-karat white gold ring with a 12-carat oval Ceylon (Sri Lankan) sapphire and 14 round diamonds.
The Duchess of Cambridge was born Catherine Elizabeth Middleton at Royal Berkshire Hospital in Reading to an upper-middle-class family.
She is the eldest of three children born to Michael Middleton and his wife, Carole, a former flight dispatcher and flight attendant, respectively, who in 1987 founded Party Pieces, a mail order private company that sells party supplies and decorations with an estimated worth of £30 million.
Michael's family has ties to British aristocracy and benefited financially from trust funds which they had established over 100 years ago. Her Middleton relatives are thought to have played host to British royalty "as long ago as 1926".
Kate has a younger sister, Pippa, and a younger brother, James.
Pippa Middleton is a socialite, author, and columnist. She began receiving media attention after her appearance as the maid of honour at Kate's wedding.
In July 2016, Pippa became engaged to James Matthews, a former professional racing driver, and now a hedge fund manager. The couple married on May 20 2017.
James Middleton is the youngest sibling, and is an English businessman.
The 'Kate Middleton Effect' is the trend that the Duchess of Cambridge is reported to have had on others, usually in relation to her style and fashion sense.
The effect began after the announcement of the couple's engagement in November 2010, which spawned something of a media frenzy.
Her wedding dress was put on display at Buckingham Palace in 2011. The display helped to raise around £8 million for the Royal Collection, as well as the charitable fund of the Duke and Duchess.