The monarch hosted a ceremony to mark the retirement of her household’s most senior official, former Lord Chamberlain Earl Peel, on Tuesday.
It was the first in-person event the Queen has held since Prince Philip’s passing on Friday at the age of 99.
The Duke of York has said his mother is bearing up stoically and the family have been rallying round to support her. Prince Andrew said his mother described the death of her husband "having left a huge void".
Listen to the The Royal Rota on The Duke of Edinburgh's life, legacy and how he will be remembered
The Duke of Cambridge pledged to uphold Philip’s wishes and continue to support his grandmother the Queen and “get on with the job”.
It was announced at the weekend the monarchy and their households would observe two weeks of royal mourning - with members of the family “continuing to undertake engagements appropriate to the circumstances,” a royal official said.
The Princess Royal took part in her first official event since the death of her father, joining the Royal College of Emergency Medicine’s Spring Conference via video call in her role as the organisation’s patron.
Prince Andrew: Queen described the death of her husband as "having left a huge void".
Former Lord Chamberlain Earl Peel, whose retirement was being marked, had overseen arrangements for the duke’s funeral.
He handed responsibility to his successor, former MI5 spy chief Baron Parker, just over a week before the duke died peacefully at Windsor Castle.
The Lord Chamberlain’s Office, led by the Queen’s Comptroller Lieutenant Colonel Michael Vernon, is tasked with the practical side of the day.
But in overall charge is Andrew Parker, Baron Parker of Minsmere, who took up his new role on April 1, following the Earl Peel’s retirement after more than 14 years in the post.
During a ceremony held at Windsor Castle, the Queen accepted her former royal aide’s wand and insignia of office.
The official engagement was recorded in the Court Circular - a daily list of the events attended by the Queen and her family.
It said: “The Earl Peel had an audience of The Queen today, delivered up his Wand and Insignia of Office as Lord Chamberlain and the Badge of Chancellor of the Royal Victorian Order and took leave upon relinquishing his appointment as Lord Chamberlain, when Her Majesty invested him with the Royal Victorian Chain.”
The Queen recently conferred a prestigious honour on the Earl Peel, making him a Permanent Lord in Waiting.
The Armed Forces are stepping up preparations for the duke’s funeral on Saturday.
It will feature servicemen and women from the Royal Navy, Royal Marines, Army and RAF, alongside top military brass.
Soldiers from the Corps of the Royal Electrical and Mechanical Engineers (REME) are reportedly working to prepare the special Land Rover – that the duke helped design – which will carry his coffin on Saturday.