A former employee at the royal household told the Daily Mail: “The Queen adores Paul.
"He is the perfect calming presence to have around in such circumstances.”
The pair are believed to be so close the Queen sometimes invites Mr Whybrew to sit down with her and watch TV, something she'll no doubt be doing a lot more of while in lockdown.
The details come after the Queen broke her silence last week amid the coronavirus pandemic.
Her Majesty shared a statement and assured the public "that my family and I stand ready to play our part".
The statement read: "As Philip and I arrive at Windsor today, we know that many individuals and families across the United Kingdom, and around the world, are entering a period of great concern and uncertainty.
"We are all being advised to change our normal routines and regular patterns of life for the greater good of the communities we live in and, in particular, to protect the most vulnerable within them.
"At times such as these, I am reminded that our nation's history has been forged by people and communities coming together to work as one, concentrating our combined efforts with a focus on the common goal.
"We are enormously thankful for the expertise and commitment of our scientists, medical practitioners and emergency and public services; but now more than any time in our recent past, we all have a vitally important part to play as individuals - today and in the coming days, weeks and months.
"Many of us will need to find new ways of staying in touch with each other and making sure that loved ones are safe. I am certain we are up to that challenge. You can be assured that my family and I stand ready to play our part."
The Queen's statement came after growing concerns for her safety.
Royal insiders have said it's likely Queen Elizabeth will stay there while the country is in the grip of the crisis.
A palace spokesman said: "As a sensible precaution and for practical reasons in the current circumstances, a number of changes are being made to The Queen’s diary.
"Her Majesty will move to Windsor Castle for the Easter period on Thursday 19th March, one week earlier than planned. It is likely The Queen will stay there beyond the Easter period.
"In consultation with the Medical Household and Government, a number of public events with large numbers of people due to have been attended by The Queen, and other Members of the Royal Family, in the coming months will be cancelled or postponed."