Buckingham Palace says Prince Philip has been transferred back to the private Prince Edward VII’s hospital to continue his recovery after a heart procedure.

The palace says the 99-year-old husband of Queen Elizabeth II underwent a successful procedure for a pre-existing heart condition at St Bartholomew’s Hospital on Wednesday.

Prince Philip is “expected to remain in hospital for continuing treatment for a number of days,'' the palace said.

Philip was admitted to the private London hospital on Feb. 16, where he was treated for an infection. On Monday he was transferred to the specialized cardiac care hospital.

Philip’s illness is not believed to be related to the coronavirus. Both Philip and the monarch received COVID-19 vaccinations in January and chose to publicize the matter to encourage others to also take the vaccine.