London — The official titles of Prince Harry and Meghan's son and daughter were updated on the U.K. royal family's website Thursday, a day after it was announced that the couple had christened their daughter Princess Lilibet Diana in California earlier this month. The two children are now listed as Prince Archie of Sussex and Princess Lilibet of Sussex on the royal family's line of succession, on which they are fifth and sixth in line to the throne.

"I can confirm that Princess Lilibet Diana was christened on Friday, March 3 by the Archbishop of Los Angeles, the Rev John Taylor," a spokesperson for the Sussexes said in a statement on Wednesday.

Lilibet was not a princess at birth because she was not a grandchild of the monarch. She gained the right to the title, however, when her grandfather King Charles III took the throne, according to rules set out by King George V in 1917.

The Wednesday announcement by the Sussexes was the first time Lilibet had been publicly called a princess. Both Lilibet and her brother Archie have been entitled to use HRH, or His or Her Royal Highness, and the prince and princess titles, under the 1917 rules, since Queen Elizabeth II died and Charles ascended the throne.

"The children's titles have been a birthright since their grandfather became Monarch," the Sussexes' Archewell organization affirmed in a statement on Thursday. "This matter has been settled for some time in alignment with Buckingham Palace."

CBS News understands that the the offer to update the royal website using the children's titles came around the time that the Duke and Duchess of Sussex learned they would be asked to vacate their royal residence in the U.K., Frogmore Cottage.

In:
• British Royal Family
• Prince Harry Duke of Sussex
• Meghan Duchess of Sussex

Haley Ott

Haley Ott is an international reporter for CBS News based in London.

Twitter