Sophie examined a knitted stage of the Royal Variety Performance featuring knitted versions of the Duke and Duchess of Edinburgh and Sir Elton John.
The knitted art had been made by residents of Brinsworth House in Twickenham, and was on display during the Royal Windsor Flower Show at the York Club in Windsor Great Park.
The duchess was joined by gardener and broadcaster Alan Titchmarsh, who is also honorary president of the event, as she sat in a carriage during the show and was shown sweet treats alongside Dame Mary Berry.
Sophie examined plants and was seen holding one up for Titchmarsh to smell during the event.