Kate Middleton curtsies to King Charles after reportedly refusing to bow for Queen Camilla

What a highbrow bow.

Kate Middleton put her royal etiquette and years of training to good use when she dropped into a curtsy worthy of the record books on Tuesday.

Wearing a stunning red hat by Jane Taylor and a matching wool cape by Catherine Walker & Co., the Princess of Wales accompanied her husband, Prince William, both 41, to greet the South Korean President Yoon Suk Yeol, 62, and his wife, First Lady Kim Keon Hee, 51, for their formal state visit to the United Kingdom.

After introductions were made, the couples arrived at the Horse Guards Parade in London to meet King Charles, 75, and Queen Camilla, 76, for the ceremonial welcome.

As Princess Kate walked up the stairs behind Prince William, who bowed his head to acknowledge his father and Camilla, she stopped at the top and dropped into the perfect curtsy to the King and Queen, mere inches away from certain disaster.

Without missing a beat, or falling down a stair, Prince Kate flashed a wide grin to the cameras before taking her place next to Prince William.

For centuries it has been tradition to greet or welcome members of the royal family with a curtsy or bow, but according to the official website, “there are no obligatory codes of behavior when meeting The Queen or a member of the Royal Family, but many people wish to observe the traditional forms.”

So it’s no surprise that when royals have their breeches in a bunch or are royally miffed, they will show their disdain by declining to curtsy to the monarch that has earned their wrath.

Such was the case at King Charles’ coronation on May 6, when Princess Kate reportedly refused to bow for Queen Camilla as she left Westminster Abbey.

In an interview on “Dan Wootton Tonight,” royal biographer Tom Bower claimed that the Princess of Wales was “angry” with the newly crowned queen over the guest list for the coronation because she was only able to invite four of her family members while Camilla had 20 people in attendance.

“Camilla brought 20 Parker Bowleses to the coronation and there were four Middletons,” Bower said, while confirming that both of Middleton’s siblings were not allowed to bring their partners.

“If you look at the coronation footage, as the king and queen leave the thrones and head for the exit of Westminster Abbey, you’ll see that everyone bows and curtsies to the king and no one moves a limb, a muscle, when Camilla passes,” continued Bower. “And that’s because they were angry with Camilla.”

Refusing to curtsy has also seemingly landed the Duchess of Sussex into hot water.

According to royal biographer Andrew Morton, 70, Prince Harry, 38, and Meghan Markle, 42, won’t return to the UK because she does not want to curtsy to Middleton when Prince William becomes king.

On Sky News’ “Sunday Morning With Trevor Phillips,” the biographer was asked about the possibility of the Duke and Duchess of Sussex coming back to Britain after moving across the pond in 2020.

“What, and have Meghan Markle curtsying to Kate Middleton?” snarked Morton. “I don’t think so.”