The Prince of Wales has arrived at King Edward VII's hospital in London to visit his father the Duke of Edinburgh.
The Duke, 99, was admitted to hospital on Tuesday evening as a "precautionary measure" after feeling unwell.
On Friday it was reported that the duke was likely to stay in hospital over the weekend and into next week for rest and observation.
A royal source said the issue was not coronavirus-related, that he was taken to hospital by car and not an ambulance, and he walked inside unaided.
Both the Duke and the Queen had their COVID-19 vaccines in January.