The 95-year-old monarch conferred the accolade on Professor Sir Huw Thomas, who is Head of the Medical Household and Physician to the Queen, in a private ceremony on Tuesday.
Concern for the health of the Queen has been heightened in recent weeks after she pulled out of a number of major engagements, spent a night in hospital and was ordered to rest by royal doctors.
It is likely to have been Prof Sir Huw who advised the head of state to take things easy after she underwent preliminary tests in King Edward VII’s Hospital on October 20.
Prof Sir Huw would have also cared for the late Duke of Edinburgh during more than 15 years service with the royal household.
While the monarch invested Prof Sir Huw separately with the Insignia of a Knight Commander of the Royal Victorian Order, her daughter the Princess Royal carried out a full investiture ceremony for scores of recipients on the Queen’s behalf the same day.
It is likely the Queen wanted to thank Prof Sir Huw personally for his care of her and the royal family.
Details appeared in the Court Circular – the daily record of official royal engagements.
Prof Sir Huw, who has been Head of the Medical Household for seven years, was made a Knight Commander at the start of 2021 in the New Year’s Honours list.
The Royal Victorian Order award is in the Queen’s personal gift and is awarded for service to the royal family.
At the time, the physician, who is also Professor of Gastrointestinal Genetics at Imperial College London’s Department of Surgery and Cancer, told Imperial of his work within the royal household: “It’s been a busy couple of years in this role, so I feel very grateful to have been recognised for my service to date.”
He added: “You very much become part of that organisation and become the personal doctor to the principal people in it, who are patients just like other patients.
“With the pandemic, the key priority of the Medical Household is trying to make sure that the people under its care are kept safe.”
Both the Queen and Philip received their Covid vaccinations, and the pair were cared for at Windsor in HMS Bubble – the nickname for their reduced household of loyal staff – during lockdown for their protection.
The duke died at the age of 99 a few weeks after he was admitted to hospital for an infection and had heart surgery for a pre-existing condition.
Prof Sir Huw was accompanied by his wife Lady Thomas during the audience.