Royal fans left shocked over Princess Charlotte and Prince George's latest appearance for this reason

Prince George and Princess Charlotte left royal fans shocked with their "growth spurt" at a Father's Day event in Sandringham.

• Prince William was joined by Prince George and Princess Charlotte at the Run Sandringham race.
• Prince George and Princess Charlotte have grown significantly since their last public appearance. 
• This follows royal news that Princess Beatrice is set to follow in Kate Middleton's footsteps as she prepares to welcome her first baby.

Prince George and Princess Charlotte made a surprise appearance alongside their father, Prince William, at Run Sandringham—a Father's Day event raising money for charity.

Prince George, seven, was dressed in a smart check shirt, with long shorts and trainers, while Princess Charlotte, six—who is nearly as tall as her brother now—wore a pink Ralph Lauren jumper to match her pink trainers.

It's the first time royal watchers have seen the Duke and Duchess of Cambridge's two eldest children together in over a year. And people were left shocked with just how much they have grown.

"Crikey, they have shot up," said one fan. While another said, "George is going to be taller than his father at this rate, and that's saying something."

Their appearance came just hours after Kate and Williams's sweet Father's Day post featured previously unseen photos of the children. 

It's been a whirlwind few days of celebrations in the Cambridge household as today marks Prince William's 39th birthday.

While covid-19 restrictions forbid him from having a big bash, it is thought Prince William will spend today surrounded by his nearest and dearest at his Kensington Palace home.

Fortunately, Kate is a dab-hand at party planning and will make things particularly special for William today.

"Kate always makes birthdays and celebrations special for William and the children," royal biographer Katie Nicholl told OK! magazine. "She's very much like her mother Carole in that respect." 

With the Cambridge children due to break up from school in a matter of weeks for the summer holidays, Prince Harry and Prince William are expected to try and work things out during an upcoming reunion trip. 

According to US Weekly, the Duke and Duchess of Cambridge are planning a secret trip to America to meet their new niece, Lilibet, and embark on "peace talks" with the Duke and Duchess of Sussex.

A palace insider said, "There’s a shared desire to move on. William and Kate want to meet Lili, and they agree it’s only fair that they visit Harry and Meghan on their home turf."

While there is still a long way to go in healing their rift, with the upcoming unveiling of Princess Diana's statue in the Sunken Gardens at Buckingham Palace, there is a general feeling that the brothers need to put their differences aside. 

"At the end of the day, William and Harry both realise blood is thicker than water. It's not doing anyone any good to be locked in this bitter feud. They're all committed to finally making the peace."