The King was cheered as he arrived at Morrisons HQ
The King told Morrisons workers he hoped bosses would "let you off at Christmas" as he visited the company's headquarters at the start of a two-day tour of Yorkshire.
Charles toured the Bradford base of the supermarket giant as hundreds of staff watched from balconies and stairwells.
As he arrived, he chatted to people who worked at stores around the region, telling them: "Thank-you for your wonderful efforts. I hope they let you off at Christmas."
Later, in a short speech, he told the staff: "It's a great joy to see you all today.
"I had no idea quite how many of you worked here at Morrisons."
After discussing his tour and work he had heard about in the community, the King said: "I can only thank you for all that, wish you every possible success in the future and, eventually, a really happy Christmas ahead."
The King was given tips on roasting potatoes as he toured the development kitchen at Morrisons, examining special dishes prepared from triple-smoked salmon and pan-roasted short-horn beef by chefs Mark Richmond and Richard Jones.
He talked to a variety of producers about sustainable livestock rearing and current issues in farming.
As he was introduced to producers of recently launched carbon-neutral eggs, Charles asked about the new rules to combat bird flu.
Claire Anderson, commercial manager of Chippendale Foods, which supplies the "Planet Friendly" eggs to Morrisons, said the royal visitor asked whether all the birds now had to be kept indoors, which she said they did.
Charles looked intrigued by how the eggs get their carbon-neutral status, by being fed on black soldier fly larvae, which themselves feed on waste products from the supermarket operation.
Ms Anderson said he also asked whether the eggs are more expensive than normal eggs which, she said, they were slightly.
The King was shown around the HQ, where about 2,000 people work, by Morrisons chief executive David Potts.
The firm set out a version of its trademark Market Street fresh food aisle in its main atrium and Charles took time to talk to butchers, fishmongers, florists and bakers, as well as apprentices working in these areas, as he voiced a liking for hake and plate steak.
He also met some of the community champions, who work on projects around the country, based at Morrisons stores.
The King told the Morrisons staff in his speech: "It has been a great pleasure to meet at least some of you and to see what a remarkable operation is run throughout this country."
He said the work done by the community champions "is so enormously heartening".
The King unveiled a plaque left Morrisons for further engagements in Bradford city centre and Leeds.
On Wednesday, he will be joined by the Queen Consort for engagements in York and Doncaster, including unveiling a statue of his late mother at York Minster.
He will also confer city status on Doncaster.
On the latest episode of the ITV News podcast Royal Rota, Royal Editor Chris Ship and Producer Lizzie Robinson discuss Prince Harry's memoir and just what happened with King Charles and COP27.