William and Kate were granted special permission by The Queen to break a royal rule this week

Here's why.

This week, The Queen has granted Kate and William special permission to break Royal protocol.

Breaking Royal tradition, she has said that the Cambridges - including the Duke and Duchess of Cambridge and their three children, George, Charlotte and William - can to jet off on holiday together.

This is unusual, as traditionally they have to adhere to an old Royal rule which bans immediate heirs of the throne from travelling together.

Yesterday, they were seen at Heathrow airport with suitcases, seemingly on their way to a well-deserved holiday.

This is the first time they will have been abroad as the family for a while because of coronavirus.

They had to ask The Queen for permission to travel together as a family of five, which she said yes too.

It's believe they jetted off from Gatwick Airport and planned the trip to coincide with the children's half term break.

Where the Royals are travelling for their holiday hasn't been confirmed.

They were photographed outside of the Windsor Suite, which is a special suite reserved for the Royal Family and other high profile celebrities when they are travelling.

Royal duties have been resumed as of late, despite The Queen having to pull out of both a two day trip to Northern Ireland and climate conference COP26 because of her health.

CornwallLive has reported that this may be one of the very last times William and Kate's family are allowed, by Royal rule, to travel together. As above, an old Royal tradition dictates that senior members of the family are prohibited from flying together.

This is supposedly to protect Royal lineage, and the rule can only be broken if Her Majesty herself says so.

George is currently eight years old, but it's believed the Royal rule comes into effect when he turns 12.

When George does turn 12, he will be required to fly separately from his father.

William and George are second and third in line to the thrown. They must fly separately in case something tragic happens to them or their method of transport.

The rule also dictates that Charles and William - and further, Charles and the Queen - shouldn't fly together.

The Cambridges have flown to Australia, Canada, Poland, Germany and New Zealand together previously.

The Royal Family’s press office told Newsround: “They had to ask the Queen for permission, but she said yes."

Wishing the Cambridges a happy break.