Prince Charles, 72, and Camilla, 73, visited a vaccination pop-up centre at Finsbury Park Mosque in north London on Tuesday.
The Prince revealed he is "thrilled" that his 99-year-old father has returned to Windsor Castle after leaving hospital and that he had "spoken to him several times".
WATCH: Charles and Camilla visit a vaccination centre at Finsbury Park Mosque
Prince Philip was reunited with the Queen at Windsor Castle after spending 28 nights as an in-patient – his longest ever hospital stay.
The Duke was first admitted to King Edward VII's hospital on 16 February for an infection, before undergoing heart surgery for a pre-existing condition at St Bartholomew's hospital.
A few days later he was transferred back to King Edward's to recuperate and to continue his treatment.
Charles visited his father at King Edward's on 20 February, making a 200-mile round-trip from his home, Highgrove, in Gloucestershire.
The Duke of Edinburgh left hospital after a four-week stay on Tuesday
Buckingham Palace said in a statement: "The Duke of Edinburgh has today been discharged from King Edward VII's Hospital and has returned to Windsor Castle, following treatment for an infection and a successful procedure for a pre-existing condition.
"His Royal Highness wishes to thank all the medical staff who looked after him at both King Edward VII's Hospital and St Bartholomew's Hospital, and everyone who has sent their good wishes."
Charles and Camilla visited a vaccination pop-up centre at Finsbury Park Mosque
During the public outing, the Duchess of Cornwall also revealed that she was given the AstraZeneca Covid-19 jab in February.
Dr John McGrath, a GP, who was administering the rollout at the mosque, asked the Duchess which vaccine she had received previously and was told AstraZeneca.
Camilla added: "Although it didn’t matter. I didn't ask. I don't even ask because I hate injections so much that I shut my eyes… whatever comes out."
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