“Kate Middleton expresses surprise over Louis turning five during royal visit, saying time is passing by quickly.”

The Princess of Wales has admitted she can’t believe her youngest son Louis has turned five after celebrating his birthday last weekend.

Kate Middleton, 41, made the admission while visiting The Baby Bank charity center in Windsor this morning, where she spoke to volunteers and helped sort newborn clothes.

And it seems the visit left the royal feeling nostalgic, as she told donation center staff she couldn’t believe her youngest son had already turned five.

It was a sentiment that royal fans had echoed over the weekend, with many saying they couldn’t help feeling “old” – as time seems to have flown by since the birth of the young royal family.

The young schoolboy was all smiles in a new photo posted to Instagram late on the eve of his 5th birthday, where his mother Kate lovingly pushed him around in a wheelbarrow.

In an instant, the youngest Wales was captured atop a pile of garden cuttings in the garden of Adelaide Cottage in Windsor near their childhood home.

The Prince is grinning from ear to ear as he peeks for the camera as he relaxes in a plaid shirt, blue Fairisle jumper and navy blue shorts to match the playful ensemble.

Royal fans expressed disbelief at how quickly the royal family has grown up.

One fan commented, “Our baby isn’t a baby anymore! Happy 5th Birthday to our Prince Louis! The best not-so-little boy!

Another said: ‘Five!!! Gosh I’m getting old. Wasn’t he born a month ago?’

A third added: ‘Happy Birthday Louis! I can’t believe daddy is five already! What a beautiful boy and two beautiful pictures.’

And one asked ‘HOW?! Where did the time go?’

Meanwhile, a fan posed a question to an even older Prince Louis: “Hands up who thinks that in 10 years teenage girls around the world will have this face and kid like a pin-up!”

‘I do! since some of the oldies are already in love with him.’

And back in time, one of them said, ‘Hard to believe this is the same boy we were waiting outside the Lindo wing!!! Time flies! Happy birthday, dear Louis!’

‘Congratulations! We have our own Louis who will be two soon. The years go so fast!’ said another.

The Instagram post has since been liked nearly a million times and received fewer than 9,000 comments.

The charming family moment was captured by Millie Pilkington, who was previously trusted by Kate and William to privately photograph their 2011 wedding reception.

Prince Louis Arthur Charles was born on April 23, 2018 in the Lindo Wing of St Mary’s Hospital in London and is the second son and youngest child of the Duke and Duchess of Cambridge.

The prince’s birthday is closely followed by that of older sister, Princess Charlotte, who will celebrate her eighth birthday on May 2 – just four days before the coronation of her grandfather, King Charles, on May 6.

Prince Louis, who is currently fourth in line to the throne, is expected to join his older siblings George, nine, and Charlotte for the coronation carriage procession, while George, second in line to the throne, is expected to play a role in the service.

It is thought that Louis will be on the balcony of Buckingham Palace along with working members of the royal family for an RAF flypast.

The new photos follow the release of a photo of the late Queen with all of her grandchildren and great-grandchildren on April 21 on what would have been her 97th birthday, which showed Louis wearing a hand-me-down shirt from George.