Lip reader confirms Kate's stern words to her children at the King's birthday

The royal family were out in force this weekend to celebrate King Charles III's birthday. 

While his birthday actually falls in November, it has become a tradition for the monarch to celebrate the occasion twice a year. Following in the footsteps of his late mother, Queen Elizabeth II, Charles celebrated on Saturday with the annual Trooping the Colour parade. 

Many royal fans were thrilled to see the Prince and Princess of Wales' three children, Prince George, Princess Charlotte and Prince Louis, taking centre stage. 

The young royals were seen enjoying a carriage ride, and later appeared on the Buckingham Palace balcony to watch the fly past. 

Over the last twelve months, Prince Louis has stolen the show at a number of events. During the late Queen's Platinum Jubilee celebrations last year, he went viral for his adorable facial expressions and cheeky behaviour. 

While he once again caught the attention of the world this weekend with his excited waves and grins, there was one moment where mum Kate had to step in and ensure that her three children were behaving. 

The little ones were spotted waving and smiling to the thousands of people who had gathered to witness the celebration, and they appeared to be very excited by the whole affair. 

After noticing this, Kate was seen saying something to George, Charlotte and Louis - and now a lip reader has confirmed exactly what the Princess said. 

According to lip reader Jeremy Freeman, the royal was instructing them on how to behave in the carriage. 

He claims that she said: "Do not look behind whilst on the coach."

However, the rebellious little royals appeared to ignore their mother's instructions as a camera shows the children continuing to look behind them. 

Kate is often praised for remaining calm with her children, but royal fans love to see George, Charlotte and Louis' unique personalities shine through during events like these.