Royal biographer Duncan Larcombe weighed in on the possibility of Prince Harry and Meghan Markle not attending King Charles III's coronation next year and believes they would rather spend it celebrating their son Archie's birthday in California.

His Majesty will be crowned alongside his wife, Queen Consort Camilla on May 6, 2023, which also happens to be Archie's fourth birthday. The author, who wrote "Prince Harry: The Inside Story," said he would not be surprised if the Sussexes opted out of the momentous occasion in London.

He explained that the Duke of Sussex, being a non-working royal, would not be expected to attend his father's coronation. He told The Sun, "There is nothing to say Prince Harry must be at the Coronation."

However, given that King Charles III's coronation falls on Archie's birthday allegedly gives Prince Harry and Meghan Markle an excuse to skip the event. Larcombe added, "The fact it clashes with Archie's birthday may well gift the Duke and Duchess of Sussex what they need. It will ultimately come down to what happens between now and next May."

The author also commented on reports of a rift between the Sussexes and the British Royal Family, specifically with Prince William and King Charles III. He surmised that "if the rift remains, few would expect Harry to attend." If "relations between them improve over the next six months then this is an event Charles will want both his sons to witness."

However, Larcombe added, "As things currently stand, I suspect Harry would be happier lighting his son's birthday cake candles that day rather than sitting in the shadows of Westminster Abbey watching his father and brother take centre stage."

Buckingham Palace has yet to release details about the coronation including the guest list. It is unclear if King Charles III will invite Prince Harry and Meghan Markle given reports that he had to scale back on the number of guests from 8,000 to 2,000. He reportedly had to cut back on inviting family members and celebrity friends.

As for Archie's birthday, Prince Harry and Meghan Markle have so far celebrated his milestones in private for the past years. They normally launch charity initiatives in line with their son's birthday celebrations.

Meghan Markle, Prince Harry and Prince William
Prince Harry in 2019 revealed that he had grown apart from his older brother Prince William Photo: AFP / Tolga AKMEN