Surprising reason Kate Middleton was forced to curtsy four times to King Charles and Queen Camilla during state visit

The British monarchy have been hosting the President of France in the UK this week, which has naturally seen the Prince and Princess of Wales in attendance to a number of high-profile meet-ups and state dinners.

Snaps of William and Kate dressed to the nines in formal attire alongside Emmanual Macron and his wife Brigitte at RAF Northolt in London have been doing the rounds online, along with others of the couple posing beside King Charles and Queen Camilla.

Videos of the royal group have also been trending on social media, one of which has puzzled viewers.

In the clip, 43-year-old Kate can be seen approaching her in-laws along with William, 41, after the French leader and his other-half greeted the King and Queen with a gracious bow.

Macron and his wife have been visiting the UK this week (Alberto Pezzali - WPA Pool/Getty Images)

When the Princess' turn arrived, however, instead of curtsying just once, Kate could be seen in the clip bobbing up and down a staggering four times.

For those in need of a reminder, despite she and William themselves being the future rulers of the country, the couple are still expected to follow formal royal protocol in front of the current Heads of State.

In the viral clip of Kate, the first two curtsies she performs are in quick succession.

At the time, however, it looks as though neither Charles, 76, nor Camilla, 77, had concluded their initial catch up with the Macrons, and the foursome were still seen gabbing away. As such, the King and Queen missed Kate's double-whammy.

Eventually, Emmanuel and Brigitte move to the side, giving their full attention to William and Kate, the latter of whom then dips down for a third curtsy, with it being vital that the King and Queen fully soak up the gesture.

Kate curtseyed four times (Samir Hussein/WireImage)

Formalities out of the way, the mother-of-three then approached Camilla directly, planting a kiss on the Queen's cheek.

Then, just to be sure, Kate gave she and the King a fourth and final curtsy.

This isn't the first time that the French state visit's formalities have raised questions this week, after Macron, 47, was spotted kissing both Camilla and Kate on their hands during their first meeting.

Whilst seen by critics as a pretty romantic gesture - or possibly, just very French - it turns out that there's actually no rules against kissing a royal, in the appropriate way, of course.

Kate then kissed Camilla on the cheek (Max Mumby/Indigo/Getty Images)

The Royal Family's official website explains: "There are no obligatory codes of behaviour when meeting The Queen or a member of the Royal Family, but many people wish to observe the traditional forms.

"For men, this is a neck bow (from the head only) whilst women do a small curtsy. Other people prefer simply to shake hands in the usual way."

And in fact, King Charles went on to greet the French First Lady, Brigitte, 72, in the same way.