The King was cheered by Morrisons workers after he wished them an early “happy Christmas” at the beginning of a two-day tour of Yorkshire.
Charles toured the Bradford HQ 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 then travelled to Bradford City Hall, where he was greeted by cheering crowds and a ‘mash-up’ of the City of Bradford Brass Band and the Punjabi Roots Academy.
Charles met young leaders from across Bradford, including Britain’s first female hijabi boxer, Safiyyah Syeed, and Yeasin Mohammed, a Rohingya refugee who fled Myanmar before coming to the UK in 2010, and now owns Sizzling Lounge restaurant in Bingley.
Mr Mohammed told the PA news agency: “He was interested to hear that people can do things like that in times of struggle. He was happy and he mentioned he was going to go to a camp.
“It’s a big dream to see someone like that when back home, we’ve seen, not even real pictures but ones people have drawn – to get the chance to meet him face-to-face and tell him my story is incredible.”
Ms Syeed, who started boxing five years ago after including it on her bucket list during a long-term illness, said: “It was amazing, he was interested in my boxing and he knew a bit about us all.
“My 18-year-old self would be screaming.”
A 96-year-old Jamaican Second World War veteran who came to Britain on the Windrush said he never imagined he would meet the King when he arrived in the UK as a young man.
Ex-RAF serviceman Alfred Gardner signed up for the war in Jamaica aged 17, arrived in the UK aged 18, returned to the Caribbean aged 22 and then settled in the UK the following year.
He was a founder member of the Jamaica Society Leeds, which the King visited on Tuesday.
After speaking to Charles, Mr Gardner, standing ram-rod straight and proudly displaying his medals, said: “In my wildest dreams I never thought I would one day meet the King.
“I have met the Prince of Wales [William], but to meet the master… what a day.
“My dad was a real royalist, a policeman, he used to say ‘All stand for the King’.
“I couldn’t pass an exam, I didn’t know English history, now I have met the King.”
The King visited the Rebellion To Romance exhibition in Leeds library which reflects on the lives of second generation West Indians who came of age in the 1970s and 1980s.
He chatted to Derek Lawrence, who has carved a career in the music industry after being helped by the Prince’s Trust to set up a record shop when he was 18.
The 62-year-old said: “I met him in 1987 and he told me he liked The Supremes. I remember I played him a few songs.
“It was great to see him again, now he is the King.”
On Wednesday, Charles 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.