Royal enthusiasts might have anticipated Buckingham Palace marking Princess Anne’s 75th birthday with a gun salute, an official photo release, or perhaps an equestrian event.

What they definitely didn’t expect was the palace to mark Friday’s milestone by announcing that King Charles’s sister had two secret stepchildren.

Interestingly, this is precisely what took place when the official royal website published a piece on Wednesday titled ’75 facts about the Princess Royal’.

The 14th ‘fact’ was that ‘Her Royal Highness also has two stepchildren from her second marriage to Sir Timothy Laurence, Tom and Amy Laurence’.

In reality, Vice Admiral Sir Tim Laurence, 70, was a bachelor until he wed the princess at Crathie Kirk, close to Balmoral, in 1992 and does not have any children, let alone ones named Tom and Amy.

Anne has two children, Peter Phillips and Zara Tindall, with her first husband, Mark Phillips. They divorced in 1992 after 19 years of marriage.

It’s not clear who first spotted the glaring error on the royal website but the article had been taken down by Wednesday evening. 

On Thursday, there was a notice on the site stating: ‘The requested page could not be found.’

The mistake seems to have been made by a member of staff using incorrect information published in an article online by Woman & Home magazine in 2023. 

There are suspicions that Artificial Intelligence software, such as ChatGPT, may have been used to write the Woman & Home article.

A palace source told the Daily Mail Thursday: ‘The facts were checked, and that one was a late addition, sourced from a reputable publication online, which unfortunately wasn’t put back through the checking process. There was no AI sourcing on our part.’

Social media users were quick to spot the mistake, with one commenting: ‘Tom and Amy Laurence? Either I’ve gone crazy or Sir Tim Laurence has secret children.’ 

The user added: ‘Pretty sure this is an error, but how did that happen? I can’t think of any Tom & Amy siblings in the extended royal family.’

Another posted: ‘That would be the best hidden royal secret ever.’

Someone else asked: ‘That is so odd? Could it be an AI mistake? Someone at BP made that list with ChatGPT but didn’t check it? Otherwise that would be one heck of a plot twist.’

A third user stated: ‘This is not true. Sir Tim does not have children from a previous relationship.’

A Buckingham Palace spokesman declines to comment.

No one at Woman & Home was available to comment.

The fact series was also published on the Royal Family official Instagram channel.

It revealed details of Anne’s birth, explaining, ‘Her Royal Highness was born Princess Anne Elizabeth Alice Louise at Clarence House on 15 August 1950, VJ Day, at 11:50 am.’ 

The fact was accompanied by a black-and-white photograph of the late Queen Elizabeth holding Princess Anne as a newborn.

The second fact read, ‘Princess Anne joined the 1st Buckingham Palace Company of Brownies and Guides in 1959.

‘This group had first been created in 1937 for her mother, then Princess Elizabeth, and was reinstalled for Princess Anne.’

The following fact revealed insight into Anne’s charitable pursuits, explaining that she supports over 399 charities, organisations, and military regiments in the UK and beyond.

The post also explained Anne’s sporting talents, writing, ‘Princess Anne was the first member of the British Royal Family to compete in an Olympic Games, when she participated as a member of the British Equestrian team at the 1976 Montreal Games.’

Elsewhere in the post, Anne was seen carrying out charity work, with the fact, ‘The Princess Royal was nominated for a Nobel Peace Prize in 1990 by President Kenneth Kaunda of Zambia.

‘She was nominated for her work as President of Save the Children across two decades.’

The next fact read, ‘In 1994, The Queen appointed The Princess Royal to the Order of the Garter. However, The Princess Royal requested to be installed as Royal Knight of the Order and not a lady.’

The impressive list didn’t stop there, with the post also adding that Anne was the first member of the Royal Family to appear as a contestant on a television quiz show when she competed on the BBC panel game, A Question of Sport.

Anne’s diligent nature was also mentioned in the fact list, explaining that she’s completed a total of 562 overseas visits and has visited every continent, making it unsurprising that she’s often dubbed the hardest working in her family.

The following fact said, ‘Her Royal Highness has been Patron of the Scottish Rugby Union since June 1986, regularly attending matches and visiting team training sessions.’

In another image, Anne was seen stepping out of a motor alongside the text, ‘The Princess Royal is the first member of the Royal Family to have a HGV license. Her Royal Highness has also driven a double-decker London bus and a police car.’

‘Her Royal Highness is Colonel-in-Chief of more than 20 British and Commonwealth regiments,’ the next fact read.

The post concluded with an image of Anne in her famous shades, writing, ‘The Princess Royal is often seen sporting Team GB sunglasses, including at high-profile events such as the London 2012 Olympics and Royal Ascot in 2021.