Princess Beatrice and Princess Eugenie excluded from their grandmother's 100th birthday celebrations

There were two key family members missing from a major royal gathering celebrating the centenary of Queen Elizabeth II's birth.

Princess Beatrice and Princess Eugenie, who are among the late monarch's grandchildren, were left out of various events marking the occasion.

The York sisters were close with their grandmother, having attended many occasions with her throughout Elizabeth II's 70-year reign.

Their absence was noticed as King Charles and Queen Camilla hosted a tea party inside Buckingham Palace on Tuesday, bringing together 190 guests along with the 11 working members of the royal family.

The Prince and Princess of Wales joined the King and Queen for the palace party, posing for a group photo before the festivities kicked off.

Pictured in the group photo were the King, 77, and Queen, 78, Prince William and Catherine, the Duke and Duchess of Edinburgh, the Princess Royal, the Duke and Duchess of Gloucester, the Duke of Kent and Princess Alexandra.

King Charles and Queen Camilla began the day of commemorations by visiting the British Museum to view models of Britain's memorial to the late Queen.

READ MORE: Harry and Meghan's bold act that left late queen 'enormously upset'

READ MORE: Glaring divide exposed in rare royal group photo taken inside palace

READ MORE: Queen Mary reprimanded by mother-in-law in front of the cameras

They were joined by the Duke and Duchess of Edinburgh and Lady Sarah Chatto, daughter of the late Princess Margaret.

Elsewhere, Princess Anne opened a new garden in Regent's Park which features a water tower and a skylight featuring a metal corgi, the late queen's favourite breed of dog.

Prince William was the only grandchild of Queen Elizabeth II invited to the palace events.

The Queen's other grandchildren – Zara Tindall, Princess Beatrice, Princess EugenieLady Louise Windsor, Peter Philips and James, Earl of Wessex, and Prince Harry were all absent.

Princess Beatrice and Princess Eugenie have been keeping a low profile of late, owing to the scandal engulfing their parents, Andrew Mountbatten-Windsor and Sarah Ferguson.

The sisters' attendance would most likely have overshadowed the occasion, taking the focus of their beloved grandmother.

Earlier this month, Beatrice and Eugenie chose not to attend the Easter service with the King and the rest of the royal family after coming to an understanding with their uncle.

But King Charles is understood to have invited his nieces to Royal Ascot in June, contrary to earlier reports the sisters were to be banned from the prestigious event.

Beatrice and Eugenie will be allowed at Royal Ascot but won't join the carriage procession, it is understood.

They have been regular fixtures at the racing meet for many years.

The York sisters are also not working royals and the palace gathering was limited to just the 11 Windsors who officially represent the monarch.

Peter and Zara, who are Princess Anne's children, have jobs away from the royal family.

Lady Louise and her brother James are both students. Lady Louise, who is 22, attends the University of St Andrews in Scotland, while the earl is 18 and in his final year at Radley College in Oxfordshire.

Prince Harry and Meghan are now back in California having just completed a successful four-day tour of Australia which blended commercial appearances with charity events.

FOLLOW US ON WHATSAPP HERE: Stay across all the latest in celebrity, lifestyle and opinion via our WhatsApp channel. No comments, no algorithm and nobody can see your private details.