The BBC's documentary Charles R: The Making of a Monarch showed previously unseen footage of the King with his grandchildren

King Charles III is known to be a doting grandfather, and fans got the chance to see some adorable evidence of his close connection to his oldest grandchildren in a new documentary.

In , which the BBC aired on Sunday evening, the King could be seen enjoying himself with Prince George and Princess Charlotte. 

In one sweet moment, captured in 2016 when the young Prince was three, Charles and George, now nine, bonded as they sat around a table at an outdoor tea party, where the young Prince clasped a glass of orange juice and his grandfather pointed to something in the distance. 

In another shot, he appeared to be holding something up to entertain Princess Charlotte, now seven, who was then just one year old, wearing a sweet blue dress with a matching bow in her hair as she gazed at the then-Prince Charles with interest. 

The King also paid tribute to the Queen Consort in the moving and intimate behind-the-scenes programme, calling her: "The best listener in the world" and saying that "she has a wonderful way with people".

 In another moment, he spoke of his love for the late Queen, poignantly explaining that he tried to call her when he was younger. 

Providing voice-over for a black-and-white clip that showed him playing with the telephone while mouthing "Mama", the monarch said: "My mama inevitably was so busy having to do all the tours abroad. I remember when I was quite young, trying to talk on the telephone, when she was miles away." 

The documentary aired less than a week before Charles and Camilla will be crowned in a spectacular ceremony. 

LOOK: King Charles and Queen Consort Camilla look so regal in new portraits ahead of the coronation

Earlier this week, it was revealed what role Prince William, Charles' eldest son and heir, is set to play in the coronation as the details are contained in the specially commissioned Coronation liturgy, which was shared by Lambeth Palace.

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