Prince Philip, 96, waved as he was driven past the front entrance to King Edward VII's Hospital in London, having left through a different exit.
The head of state's comment suggests that although she has not visited her husband - who was spending his 10th day in hospital and is known to prefer no fuss - they have been in contact.
The Duke of Edinburgh leaving the King Edward VII Hospital in London after recovering from a planned surgery last Wednesday to replace his joint with a prosthetic implant.
"The Duke will continue his recovery at Windsor", the Palace shared in a statement on Friday.
Daughter Princess Anne was the only member of the family seen visiting the royal patriarch in hospital.
Queen Elizabeth, 91, speaking with well-wishers at an engagement in Windsor, said Philip was "getting on very well".
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Prince Philip was forced to miss Easter religious services due to the problem with his hip and has had various health complaints in recent years.
It's been a nail-biting few days for the royal family following Prince Philip's hip operation.
He was also not present at two other events at Windsor Castle - the Royal Maundy Service at St George's Chapel on March 29, and a parade on March 22 to mark Prince Andrew's appointment as Colonel of the Grenadier Guards.
His final solo engagement was in August past year, when he reviewed a parade of Royal Marines outside Buckingham Palace in his capacity as Captain General of the Corps.
Prince Philip, Duke of Edinburgh attends Sunday Service at St Peter and St Paul Church in West Newton on February 4, 2018 in King's Lynn, United Kingdom.