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.

An ambulance leaves the St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)

An ambulance leaves the St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)

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.

Members of the media stand outside the main entrance of St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)

Members of the media stand outside the main entrance of St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)

Members of the media stand outside the main entrance of St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)

Members of the media stand outside the main entrance of St Bartholomew's Hospital where Britain's Prince Philip is being treated in London, Friday, March 5, 2021. Buckingham Palace says Prince Philip has had a successful heart procedure in a London hospital. The palace says the 99-year-old Duke of Edinburgh, the husband of Queen Elizabeth II, "underwent a successful procedure for a pre-existing heart condition at St Bartholomew's Hospital." (AP PhotoFrank Augstein)