The change was made on Thursday morning, with the entries in the line of succession for Archie and Lilibet now reading Prince Archie Harrison of Sussex and Princess Lilibet Diana of Sussex.
It comes after Meghan and Harry used their daughter’s title for the first time as they confirmed that Lili had been christened in an intimate ceremony at their home in Montecito.
A spokesperson for the couple said: “I can confirm that Princess Lilibet Diana was christened on Friday, March 3 by the Bishop of Los Angeles, the Rev John Taylor.”
King Charles agreed that the Duke of Sussex’s children should use their royal titles at the end of 2022 – despite the fact that Harry and Meghan have stepped back as working royals.
It’s believed the couple will use their children’s titles in formal settings, but not in everyday conversational use.
They are said to be keen to not deny their children their birthright but to allow them the chance to decide for themselves when older whether to drop or keep using the titles.
The rules set out by King George V in 1917 mean Archie and Lili, as the children of a son of a sovereign, are automatically a prince and a princess.
As the children of a son of the King, they would also have been entitled to be styled His Royal Highness and Her Royal Highness upon his accession, but the style comes from their father and Harry’s HRH status has been in abeyance since his departure from royal life.