The heir to the throne and Prime Minister David Cameron were greeted by carol singers and snow as they visited 14 personnel staff who are being treated at Birmingham's Queen Elizabeth Hospital.
The dad-of-two royal spent 20 minutes chatting to hospital staff and military carers before speaking to the injured soldiers at the dedicated 32-bed ward run by the Royal Center for Defence Medicine (RCDM).
Prince Charles, who is a regular visitor to the unit, had invited Mr Cameron to join him for a tour of the RCDM, which moved its medical facilities to the new £545million hospital from the nearby Selly Oak hospital in June.
Helen Gyves, matron for critical care, said the prince showed a deep interest in the military patients, some of them severely injured.
Ms Gyves said: "They particularly love Prince Charles. From the military point of view, he is their icon.
"He always comes throughout the year but it's turning into a bit of a tradition that he comes at Christmas.
"He knows which regiment each patient is from and he often knows how their injuries have happened.
"To them, for him to come is very special."
