Lip reader reveals Prince William's patient response to Prince Louis' brutal comment during rare public appearance

A savage remark that seven-year-old Prince Louis directed at his father over the weekend is once again hitting headlines - alongside Prince William's reaction to the viral moment.

The pair were joined by Kate Middleton in attendance at this year's VE Day parade in London, along with Louis' two elder siblings, George, 11, and Charlotte, 10.

The British event commemorated 80 years since Germany's surrender in WWII was accepted, and saw the royal family-of-five seated together on the balcony of Buckingham Palace.

Apparently, it was during the parade that eagle-eyed onlookers spotted Prince Louis leaning towards his father, William, 42, who was seated beside him.

The family were seen on Buckingham Palace balcony (Chris Jackson/Getty Images)

Lip reading expert Nicola Hickling believes the youngster the commented on the dreary weather.

Brushing raindrops off the future king's shoulder, Hickling told The Sun she believes William firstly told Louis: "Look at this I think it's going to be quite wet today."

She believes the Wales' youngest then replied with a brutal quip: "Wasn't this supposed to be fun?"

According to the body language pro, William was able to calmly dismiss Louis' comment.

"It is son," she believes he replied, claiming he also said 'you will never forget this' before explaining how the parade will work.

"They will come along here, and then go towards there, and then we will make our way back," he said.

William reportedly then added: "It's not going to be long and I want you to be taking an interest."

Louis' big brother George - also a future king - then chimed in on the discussion, telling the pair: "I’ve got something in my eye."

The family set the internet ablaze for several reasons (Toby Melville - WPA Pool/Getty Images)

Hickling also analysed another moment between Princess Charlotte and her mother, with Kate reportedly asking her daughter from the sidelines: "Doesn't papa look smart today?"

A third moment also saw the mischievous Prince Louis lovingly mimicking his brother George.

Footage shared by Sky News focused on the siblings, with George seen running his fingers through his locks to move it out of his face.

In the seconds that followed, Louis copied the move with an obvious display of exaggeration - sending a hoard royal fans rushing to social media to share their reactions.

Commenting on Twitter, one user laughed: "Prince Louis copying his brother Prince George is so funny."

"I cannot with Prince Louis. Look at him mimicking Prince George and adding some ‘snazz’ to it. He is truly the moment," penned a second.

A third quipped: "That child IS EXTRA."