Charles and Camilla toured the show, which saw dozens of local businesses exhibiting their wares.
WATCH: Prince Charles and Duchess Camilla arrive at Jubilee Big Lunch
To commemorate the occasion, the pair were presented with a beautiful harvest jug created by St Ives-based potter Adrian Brough. The impressive creation was adorned with flowers and sheaves of wheat.
The royal couple appeared to be in high spirits on the day, as they were captured enjoying different food and beverages at the event. Camilla even took a memento home for her food critic son, Tom Parker-Bowles.
The Prince and the Duchess received a gift © PA Images
Scott Hall, of Cornish Chillies said: "Charles was wondering how hot our sauces were, and we said they are anything from mild to super hot.
"Camilla said she wanted to get some for her son (food critic) Tom Parker Bowles."
Camilla was also spotted visiting the dog show tent, where she closely admired terriers who were competing to be named top dog, before going to view the flower tent.
The pair also sampled drinks including sparkling cider © PA Images
The Prince attended to a matter close to his heart as he met with the managing team of the Duchy of Cornwall, including young farmers.
Charles chatted to the aspiring farmers about their sustainability goals as the duchy has a "sustainable stewardship" initiative to help future farmers survive and reach environmental target.
Will Kitto, of Higher Coombe Farm Prince said the Prince had discussed their sustainability plans and the current cost-of-living crisis.
Camilla got a close view of the dogs in show © PA Images
Prime Minister Boris Johnson also made a fly-in appearance at the event.
The 57-year-old visited the cattle tent and sheep tent, spoke to various traders in the exhibition centre, and also posed for selfies with members of the public.
Tweeting about the event, he penned: "I had a fantastic day out at the @RoyalCornwall show, meeting our incredible farmers and rural communities that produce the best food and drink in the world."
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