A new birthday rule under Queen Elizabeth II is still in force, which means it’ll be an even bigger snub than ever before if the Royal Family do not wish Prince Harry a happy birthday publicly next week.

Prince Harry walking

Prince Harry will turn 40 next week (Image: Juancho Torres/Anadolu via Getty Images)

Prince Harry is set to turn 40 next week, with  a huge birthday bash reportedly planned for the Duke of Sussex’s special day.

Now living in California, the prince will be celebrating his birthday on September 15 with his wife Meghan Markle, their children, and a whole host of A list celebrity pals.

However, while it is unlikely that any members of the Royal Family will fly over the pond to join in with the party, many are expecting the family to acknowledge the prince in some way under a rule set by the late Queen.

GB News guest issues warning to Prince Harry and Meghan Markle

According to The Sun’s former royal correspondent Charles Rae, non-working royals will only get a public greeting under a certain circumstance under the monarch’s new social media rule.

Speaking to GB News, Rae said this was when “their birthday ends in a zero”, as this tends to mark milestones.

This means that Harry, who will be turning 40 next week, should be expecting a public birthday wish from senior members of the Royal Family, including the King, according to the rule.

Although they no longer tend to discuss Prince Harry on Royal Family social media channels, to not share a greeting on his birthday is likely to be considered more of a snub than before and could suggest the family rift is as big as many people believe it to be.

While it is clear Prince William has no intention to spread brotherly love this year, the King is thought to maintain contact with Harry, who flew over to the UK immediately after finding out about the King’s cancer diagnosis.

Harry spent less than an hour with his father before flying home again, with no details of their brief discussion coming to the surface.

Prince Harry at the coronation

The Royal Family could mark his milestone birthday (Image: UI MOK/POOL/AFP via Getty Images)

He did not see his brother during his brief visit.

As well as his father, Harry is also believed to have maintained good relationships with his cousins while living in America, including Eugenie and Beatrice.

Although they have not been publicly spotted together for a while, there are no signs of rifts between the cousins, who were saved from being mentioned in Harry’s memoir Spare.

Despite the family complications, it is unlikely that any celebrations will be held for Harry’s milestone birthday in the UK, with the duke set to jet off to New York City just days after his California party.