The Duchess of Cambridge, along with her husband, Prince William, went along to a reception held at Guildhall by the former Lord Mayor where she spoke to an attendee who asked how Her Majesty was doing.
WATCH: The Duchess of Cambridge shares a joke with Princess Anne
The attendee, named Gill Smallwood from Bolton, told PA that Kate had said in response to her query: "Yes, she [the Queen] was fine, it was just very tiring yesterday" before adding that the monarch "had a lovely, lovely time."
On Thursday evening, it was announced by Buckingham Palace that the Queen would not be attending Friday's scheduled events for her Platinum Jubilee due to feeling "discomfort".
A statement explained that Her Majesty "greatly enjoyed her birthday celebration and the flypast in London during the Trooping the Colour parade."
The Duchess of Cambridge spoke to an attendee about the Queen on Friday
The Duchess, who wowed in a yellow dress by Emilia Wickstead with a matching hat, also spoke about her three children, Prince George, Princess Charlotte, and Prince Louis, who joined their royal parents on the balcony following the Trooping the Colour on Thursday. Kate told Gill that the three children "had a lovely time", attending the ceremony.
Joining the Duke and Duchess of Cambridge for the reception, held by the former lord mayor Sir David Wootton and Colonel Simon Duckworth, were Prince Charles and Camilla, Anne, Princess Royal, as well as Princesses Eugenie and Beatrice along with their respective partners.
Kate said Her Majesty was "fine" following the Trooping the Colour
However, despite making an appearance for the Service of Thanksgiving, the Duke and Duchess of Sussex did not travel to Guildhall for the reception. A reason for their absence has not been explained by Prince Harry and Meghan Markle themselves, but the reason is likely to be that since they stepped back from their roles as senior working members of the royal family in 2020, they have wanted to keep a low profile.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity and royal news delivered directly to your inbox.