The Duke of Edinburgh is expected to take it easy as he celebrates his 91st birthday just a day after leaving hospital.
Philip was discharged from King Edward VII Hospital in central London on Saturday after spending five days there having treatment for a bladder infection.
A spokesman for Buckingham Palace would only say that he would be spending the day "privately".
He said: "The Duke of Edinburgh continues to make a good recovery and he will continue his convalescence at home."
The Duke, who is usually known for being fighting fit for his age, previously suffered a health scare over Christmas when he received treatment for a blocked coronary artery.
Then the Duke was back carrying out engagements within a matter of weeks and in his grandson Prince Harry said the operation had given him "a new spurt of life".
On Saturday he was already showing signs of his acerbic wit by answering one reporter who asked him if he was feeling better: "Well, I wouldn't be coming out if I wasn't."
Philip received a number of visitors during his hospital stay, including his grandsons, the Duke of Cambridge and Prince Harry who paid a short, private visit on Friday.
William visited his grandfather while on leave from his RAF Search and Rescue duties. Harry, meanwhile, was spending the week since the Diamond Jubilee celebrations on pre-deployment training at Wattisham in Suffolk.
The Queen, the Duke of York, the Earl and Countess of Wessex and their children, Louise and James also went to see him during his stay.