A very happy birthday to the adorable Prince Louis of Cambridge, who celebrates his fourth birthday on 23 April!
MORE: The Duke and Duchess of Cambridge's holiday hobby they've passed on to their children
The youngest child of the Duke and Duchess of Cambridge has almost reached school age and no doubt there will be much fun in the royal household to mark his special day. We wonder what presents Louis' siblings Prince George and Princess Charlotte will give him?
WATCH: Learn about Prince Louis!
Below, HELLO! takes a look back at Prince Louis' milestone moments in his first four years of life – from his christening, to his first time at the polo and his official birthday pictures.
Prince Louis' birth
Aw, who remembers this snap? Prince William and Duchess Kate presented their new baby boy to the world on the steps of the Lindon Wing of St Mary's Hospital in London on 23 April 2018.
Little Louis was born at 11:01am, weighing 8lbs 7oz, and was declared fifth in line to the throne.
MORE: Duchess Kate reveals dream holiday destination she wants to take George, Charlotte and Louis
Louis' christening day
Angelic Louis looked so sweet wearing the royal christening gown for his baptism on 9 July 2018.
Here, his mother Kate carried her baby boy to his christening service at St James's Palace in London.
First Christmas photo!
How cute does Louis look in his first royal Christmas photograph?!
Photo credit: Matt Porteous
The Duke and Duchess of Cambridge shared the picture, which showed their three children at their Norfolk home, Anmer Hall.
READ: Prince Harry and Prince William celebrate baby joy with close friends
Louis turns one
Photo credit: Duchess of Cambridge
The young Prince was utterly adorable in his first birthday portrait, taken by his mother at their Norfolk home. He looked so smart in his navy trousers and cosy red jumper.
Louis' first Trooping the Colour
It was wonderful to see Prince Louis make his first-ever appearance at Trooping the Colour in June 2019.
The youngest Cambridge child stuck close to dad William for the Royal Air Force flypast, which the royals watched from the balcony of Buckingham Palace.
First trip to the polo
Duchess Kate introduced Louis to the polo in July 2019, as the family gathered to watch dad William compete in The King Power Royal Charity Polo Day at Billingbear Polo Club in Wokingham.
Louis turns two!
Photo credit: Duchess of Cambridge
We loved this photo of young Louis taken by the Duchess to celebrate his second birthday. Having a blast covered in paint, the Prince smiled for the camera on his special day.
Prince Louis meets Sir David Attenborough
It was a special occasion for the Cambridge children as they met a true hero, nature broadcaster Sir David Attenborough.
The photographs were taken in the gardens of Kensington Palace, and we're sure young Louis looked on in awe as Sir David presented his older brother George with a real shark's tooth!
Louis' first theatre trip
It was a trip to the pantomime for Louis and his siblings in December 2020.
The Cambridges attended a special pantomime performance at London's Palladium Theatre, to thank key workers and their families for their efforts throughout the pandemic.
Louis turns three and starts nursery
Royal fans were treated to this fabulous photo of Prince Louis on his bike for his third birthday photograph.
Photo credit: Duchess of Cambridge
The picture was once again taken by his mother, this time snapped before he left for his first day of nursery.
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