Prince Charles made the 200-mile round-trip to see his father in hospital after not seeing him since before Christmas, reports say.
It is understood Charles wanted to visit the Duke of Edinburgh due to the 99-year-old’s extended stay in hospital.
He is the first member of the royal family to visit Philip, who was admitted on Tuesday evening as a precautionary measure after feeling unwell.
Philip has now spent five nights at King Edward VII’s hospital in London, after walking unaided into the medical centre.
A hospital spokesperson previously said visitors would only be allowed under ‘exceptional circumstances’, due to Covid-19 restrictions.
Charles arrived at the hospital at around 3.20pm on Saturday in a grey Tesla car, and exited the vehicle wearing a face mask, before leaving around 30 minutes later.
The prince travelled from his home in Highgrove, Gloucestershire, to the hospital in the capital.
A Clarence House spokesman confirmed he returned to Highgrove following his visit.
Prince of Wales arrives at London hospital to visit father