KATE Middleton married Prince William in 2011, and they have since had three children who are third, fourth and fifth in the line to the throne.
But how old is the royal mum and when did she meet her royal husband Wills?
How old is Kate Middleton?
Catherine Elizabeth Middleton was born on January 9, 1982 at Royal Berkshire Hospital in Reading.
This currently makes the Duchess of Cambridge 40 years old, which she recently celebrated by releasing a selection of new portraits taken at Kew Gardens.
Kate grew up in Berkshire with her family - her parents Michael and Carole Middleton, her brother James and sister Pippa.
Kensington Palace confirmed the Duchess of Cambridge, along with her husband Prince William, had visited their nephew, Harry and Meghan's son, Archie, more than a week after he was born.
Prince Harry and Meghan had already introduced him to his great-grandparents, the Queen and Prince Philip, along with Meghan’s mum Doria Ragland.
Who are Kate Middleton's brother and sister?
Kate has a younger sister and brother.
Philippa Middleton, known to most as Pippa, is the middle child of the three Middleton children.
The 35-year-old socialite graduated from the University of Edinburgh with a degree in English literature, something she later put to use by releasing her own non-fiction book, Celebrate, in 2012.
Pippa married James Matthews in a relaxed but lavish intimate ceremony at her local church, St Mark’s Church in Englefield on May 20, 2017, and announced they were expecting their first child on April 22, 2018.
Kate's younger brother James is 32 years old and is the proud owner of novelty marshmallow company Boomf.
He also runs the Cake Kit Company, which delivers bespoke sweet treats and baking kits for special occasions.
Who are Kate Middleton's parents and what do they do?
Michael and Carole Middleton are the mum and dad of the Duchess of Cambridge as well as younger children Pippa and James.
Michael, 69, was born into a wealthy family with ties to aristocracy and went to the prestigious Clifton College in Bristol.
While 63-year-old Carole was born in London to a relatively normal family and grew up in Southall.
The couple met when working as British Airways cabin crew and have been married for more than 37 years.
Carole gave birth to their first child Catherine, more commonly known as Kate, in 1982.
Pippa followed a year later and in 1987 they completed their family when son James was born.
In the same year they set up the business Party Pieces, after Carole realised she could make money from creating party bags.
The firm grew into a highly successful mail-order party supplies business and by 1995, they had moved to the Berkshire village of Bucklebury.
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Which school and university did Kate Middleton go to?
From the age of four, Kate went to St Andrew's School - a private school in Berkshire - where in later years she boarded part-time.
She then studied at Downe House and Marlborough College in Wiltshire.
Kate took art history in Scotland at the University of St Andrews.
It was while studying at university that she met her future husband Prince William in 2001.