King Charles muttered "Dear, oh dear" as he greeted Liz Truss at Buckingham Palace on Wednesday night.
The monarch was hosting the Prime Minister in one of the palace's large reception rooms after an earlier meeting with the King and Queen of Malaysia.
A clip released by the Palace taken at the beginning of their weekly audience shows a pair of double doors opened by servants and Ms Truss being escorted inside by the King's equerry.
"Prime Minister, Your Majesty," the equerry announces.
Ms Truss steps forward to shake hands with the King, bowing as she does so.
"Your Majesty, great to see you again," she says.
Charles, smiling, replies: "Back again?"
Ms Truss adds: "Well, it's a great pleasure."
The King replies: "Dear, oh dear. Anyway."
It came after Ms Truss faced Prime Minister's Questions in Parliament, where she insisted she would not cut spending to balance the books as economists and the financial markets continued to question her plans.
Ms Truss told MPs she was "absolutely" not planning public spending reductions, but insisted taxpayers' money would be used well.
Separately, on Wednesday afternoon King Charles also met the King and Queen of Malaysia, known as the Yang di-Pertuan Agong and the Raja Permaisuri Agong.
