Prince Louis beams as he's pushed in wheelbarrow by Kate ahead …
The Prince and Princess of Wales have released an adorable photo of their youngest son, Louis, being pushed in a wheelbarrow to celebrate his birthday. The photograph shows the smiling youngster wearing a blue woolly jumper, shirt and blue shorts while sitting on top of leaves and grass and holding on to the wheelbarrow, as Kate laughs. It is one of two pictures taken by photographer Millie Pilkington earlier this month on the Windsor Estate.
The other is a close-up of the beaming prince, showing how quickly William and Kate's youngest child is growing up. They have been released to mark Louis turning five on Sunday, and his mum is expected to follow a sweet tradition by staying up late tonight to make him his very own cake.
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The youngster sits on top of leaves and grass while holding on to the wheelbarrow, as Kate laughs (Kensington Palace)
The other image is a close-up of the beaming prince (Kensington Palace)
Last year, to mark the occasion, the proud parents released a series of photos showing Louis grinning for the camera while playing in the sand with a bright orange cricket ball. Those pictures were taken in Norfolk, with royal fans suggesting he resembled both his mum and his dad.
Kate has previously taken to snapping pictures of her children on their birthdays to celebrate their milestones with the nation. Some images have taken a sports theme, such as their eldest Prince George's sixth birthday when he donned an England football clip.
The Prince and Princess of Wales with their children during the Easter Sunday Service in Windsor earlier this month (Tim Rooke/REX/Shutterstock)
They have also shown a special nod to family members, with George marking his eighth birthday by sitting on a Land Rover Defender - a car used by Prince Philip, the late Duke of Edinburgh. The next royal birthday to celebrate will be that of Princess Charlotte, who turns eight on May 2 - just days before King Charles' Coronation.
Louis is expected to accompany his siblings in the procession from Westminster Abbey which will follow the King's coronation on May 6, according to newspaper reports. He was not at the Queen's state funeral at the abbey in September and is thought to have been considered too young to attend the service with his parents.
Charles and Prince Louis watching the Platinum Jubilee Pageant together last year (Getty Images)
The family live in Adelaide Cottage in Windsor's Home Park and Louis attends the private Lambrook School near Ascot in Berkshire alongside George and Charlotte. Louis is fourth in line to the throne and was born on St George's Day - April 23 - in 2018 in the private Lindo Wing of St Mary's Hospital in Paddington, London, weighing 8lb 7oz.
He was christened Louis Arthur Charles at 11 weeks old, by the Archbishop of Canterbury Justin Welby, at the Chapel Royal, St James's Palace, in front of friends and family.
The 74-year-old monarch has five grandchildren, and has previously spoken about how proud and happy he is to be a grandad.
One of the most adorable moments from the late Queen's Platinum Jubilee celebrations last year saw him allow Louis to climb up onto his knee for a cuddle as they watched the Pageant together.