Prince Harry is set to lose his HRH title at an exhibition for his late mother Princess Diana after an "administrative error".
Harry, 36, and William, 38, had donated two gowns worn by their mother to the Royal Style in the Making show.
According to MailOnline, the gowns, which include her wedding dress, were placed on display at Kensington Palace last week, with the placard "Lent by HRH the Duke of Cambridge and HRH the Duke of Sussex".
However, as per the terms of the Sandringham summit, the Sussexes were allowed to keep, but not use, their HRH titles.
As such, notices at the exhibition will be changed to reflect Harry's decision to step back from royal life in early 2020.

A spokesman for the Royal Collection Trust said the dresses were "loaned by HRH the Duke of Cambridge and the Duke of Sussex", per the paper.
They added: "Due to an administrative error, for which the Royal Collection Trust was responsible, the labels were incorrect and will be updated."
The two dresses include the Princess of Wales' iconic ivory taffeta and lace wedding gown, which was designed by David and Elizabeth Emanuel. The beloved royal wore the gown during her wedding to Prince Charles at St Paul's Cathedral in 1981.
The second dress donated by Prince William and Prince Harry is Diana's wedding day going-away outfit - a peach skirt suit, which was designed by Bellville Sassoon.
The Duke and Duchess of Sussex announced in January 2020 that they would be stepping down as senior royals.

They wrote in a statement: "After many months of reflection and internal discussions, we have chosen to make a transition this year in starting to carve out a progressive new role within this institution.
"We intend to step back as ‘senior’ members of the Royal Family and work to become financially independent while continuing to fully support Her Majesty The Queen."
Following the announcement, it was decided that the couple would no longer use their HRH titles.
A Palace spokesman said in a statement at the time: "With The Queen’s blessing, the Sussexes will continue to maintain their private patronages and associations.
"While they can no longer formally represent The Queen, the Sussexes have made clear that everything they do will continue to uphold the values of Her Majesty.
"The Sussexes will not use their HRH titles as they are no longer working members of the Royal Family."