The Duchess of Cambridge is missing her husband Prince William "terribly", she told a well-wisher on Thursday.
Kate was in Leicester for the first stop of the Diamond Jubilee tour.
William is currently serving in the Falkland Islands with the Royal Air Force.
Laura Murphy, 30, who stood in the crowds outside Leicester Cathedral to meet the Royal party, asked the duchess about how she was getting on without her husband.
She told the Press Association that she asked "'how's William?' and she said 'he's fine - I'm missing him terribly'."
"She was really smiley. Really happy."
Murphy said she asked Kate how she was doing without her husband. She said the Duchess replied: "I'm being well looked after."
The Duchess was joined by the Queen and the Duke of Edinburgh for the visit to Leicester.
Well-wishers waving Union flags were on hand at the city's station as the royal party alighted from the 10:15 Nottingham service from St Pancras International in London.
Their first destination was De Montfort University, with a stop in De Montfort Square en route to watch cultural dances.
The Queen and Kate were also watching a student fashion parade at the university, where a group of six budding designers have been gearing up for their meeting with fashion icon Kate.
As part of her visit to the university, the Duchess chose a pair of shoes from a selection created by students.
Winning designer Becka Hunt, 20, said she could not believe her shoes will now be made for Kate.
She said: "I really just can't believe it. I'm overwhelmed.
"She came over and said she loved all the designs. I cannot believe I've been chosen."
Miss Hunt said her design was inspired by 19th century elegance and the blue colour was taken from the Duchess's engagement ring.
Students who talked to the royal visitors outside the university were bowled over.
Lingerie design student Polly Shelton, 21, said: "I told Kate she looked gorgeous and she said 'I like your lipstick'.
"I can't believe it. She loves my lipstick. I can't even remember what colour it is. Then she smiled and walked off. But that's enough for me."
The Royal party were greeted at Leicester Cathedral by a huge cheer from the thousands of waiting people.
The centre of Leicester was brought to a standstill as thousands of people crammed into the main shopping area to see the royal visitors.
Every reasonable vantage point around the landmark clock tower was taken hours before the Queen was due to arrive.
People stood five or six deep behind the barriers around the central area, with many saying they had been there since early this morning.
There were signs of the easy and warm relationship between the three royals as they signed the commemorative certificate.
After the Queen had signed her name, "Elizabeth R", the Duke stepped forward and just as he was about to put pen to paper - using his own pen which he removed from his pocket - his wife lightly batted his hand away to direct him to a different area of the paper.
After signing "Catherine", Kate put the pen down and was just about to walk away when the Duke motioned to her that she had used and was just about to leave his pen.
There were peals of laughter from people gathered in the foyer as she darted forward to pick it up and, with a broad smile, handed it back to the Duke saying, "Oh sorry".
The royals were presented with more gifts of flowers and cards as they left the building and got into a waiting car to go on to their final stop in the city centre.