You'll never guess which key Royal Family member went 'undercover' for MI5 and MI6

FYI, it wasn't the Queen or Kate Middleton..

A vital part of being a Royal family member are the engagements, events and day-to-day Royal duties you're required to attend to.

But did you know that one of the most well-known members actually did a three week stint undercover at MI5 and MI6 back in 2019?

As per an article in Tatler, one senior Royal spent time 'undercover with British spies, becoming au fait with the dealings of MI5, MI6 and GCHQ.'

Wondering whether the Royal fit in or stood out like a sore thumb? The newspaper shared that they held their own 'comfortably' among some 'highly skilled analysts and operators.'

We know that the Queen is thought to carry a penknife and be versed in her own handbag signalling, just in case of emergency... but which Royal actually went undercover as a spy?

Spoiler alert: it was actually Prince William, husband to Kate Middleton, father to George, Charlotte and Louis and second in line to the throne, after Prince Charles.

It's reported that the Duke spent twenty one days at MI5, MI6 and GCHQ - seven at each - over the course of three weeks.

At the MI6 headquarters, he worked with the Secret Intelligence Service (SIS) who deal with foreign threats and collect valuable information from overseas. Buckingham Palace confirmed that William observed officers navigating threatening situations to ensure the UK came to no harm.

Next up, he spent the week at MI5, where it's reported he shadowed counter-terrorism agents as they carried out their day-to-day surveillance.

To wrap up his three weeks undercover, The Guardian report that he completed an 'assignment at GCHQ in Cheltenham.' That's the UK's intelligence and cyber security agency, FYI. We wonder what that could have included then...

Representatives from Buckingham Palace confirmed that the Duke spent time being trained on all the latest technology and further understanding how it can 'identify, analyse and disrupt threats.'

Prince William said on his time undercover: “Spending time inside our security and intelligence agencies, understanding more about the vital contribution they make to our national security, was a truly humbling experience."

“These agencies are full of people from everyday backgrounds doing the most extraordinary work to keep us safe.

"They work in secret, often not even able to tell their family and friends about the work they do or the stresses they face. They are driven by an unrivalled patriotism and dedication to upholding the values of this country. We all owe them deep gratitude for the difficult and dangerous work they do.”

"This was a rare opportunity to expose, in detail, the technical ingenuity and problem-solving skills needed on a daily basis to help keep the UK safe.”

So what do you reckon - has the Prince got a new career as a spy just waiting to happen?