A new photograph of Prince Louis and his mother the Duchess of Cambridge has been released to mark his christening.

The baby prince is pictured alert and with a wide open-mouth smile as he is held upright in Kate’s arms.

Kensington Palace tweeted: “The duke and duchess hope that everyone enjoys this lovely photograph of Prince Louis as much as they do.”

The informal shot comes from William and Kate’s private photographs of the family celebration, but they liked it so much they decided to release it.

It was taken by Matt Porteous, chosen by the duke and duchess to to be their private photographer for the day, at Clarence House after Louis was baptised in The Chapel Royal at St James’s Palace last Monday.

It follows the release of four other images by their official photographer Matt Holyoak.

Prince Louis christening
A photograph taken by Matt Holyoak in the Morning Room at Clarence House (Matt Holyoak/Camera Press)

In a royal family photo, the Cambridge five sit in the morning room at Clarence House, with Louis in Kate’s arms, Princess Charlotte gazing across at her baby brother and Prince George sitting on William’s lap with a wide smile on his face.

Standing behind them are the Prince of Wales and the Duchess of Cornwall, along with the Duke and Duchess of Sussex, with Meghan linking her hand through Harry’s arm.

In a big family photo, Kate and William are joined by their children, along with Harry and Meghan, Charles and Camilla, and the Middleton family including Kate’s sister Pippa Matthews and her husband James.

Prince Louis christening
The ceremony took place on July 9 (Matt Holyoak/Camera Press)

A third photo of the Cambridge family by themselves features Kate smiling down at Louis in her arms, while George stands with one hand in his pocket and Charlotte leans into the trailing christening gown.

A final image shows Kate and Louis in the garden at Clarence House, with the mother-of-three looking down at the bright-eyed royal baby in her arms.

Mr Holyoak said: “I was truly honoured at being asked to take the official photographs at the christening of Prince Louis, and to witness at first hand such a happy event.

Prince Louis christening
Kate and Louis pictured in the garden at Clarence House (Matt Holyoak/Camera Press)

“Everyone was so relaxed and in such good spirits, it was an absolute pleasure.

“I only hope I have captured some of that joy in my photographs.”

Louis was sound asleep as he was carried into the Chapel Royal by Kate for the christening ceremony which lasted 40 minutes.

After the ceremony, the baby prince looked content and wiggled his fingers as Kate gazed down and beamed at him as she held him in her arms.

With Prince George and Princess Charlotte joining their parents for Louis’s big day, it was the first time the Cambridges were seen together as a family of five.

Mr Porteous also took images of Prince George in 2016 to mark his third birthday, including one in which the youngster held an ice cream under the nose of family dog Lupo.

Prince George’s third birthday
Prince George and the family dog Lupo in 2016 (Matt Porteous/PA)

He is a director of Studio M, an award-winning creative studio which specialises in portrait and commercial photography and film, and is based on the island of Jersey.

Celebrity photographer Mr Holyoak has worked with a host of stars and his photos have regularly been splashed on the covers of magazines such as Harper’s Bazaar, Shortlist and Dazed and Confused.

He photographed the Queen and the Duke of Edinburgh as part of a series of portraits released to mark their 70th wedding anniversary.