Confusion reigned on Tuesday over the announcement by the British Army of Catherine, Princess of Wales's first official duty since undergoing surgery at her father-in-law King Charles III's birthday celebrations in June.

The British Army initially said that Catherine, who is married to heir to the throne Prince William, would review soldiers on 8 June as part of the annual Trooping the Colour ceremony.

Kate and William's Kensington Palace office did not formally confirm her appearance and the Army later removed a reference to it from its website.

That came just 24 hours after Kate was spotted in public for the first time since she underwent abdominal surgery in January, according to photos published by US outlet TMZ.

The army's website listed the king, who is being treated for cancer, as attending the main military parade on June 15, which marks his official birthday.

Charles, 75, on Tuesday held an in-person audience with finance minister Jeremy Hunt, who delivers the government's budget on Wednesday.

The British head of state, dressed in a blue suit and a light tie, was photographed shaking hands with Hunt as he welcomed him at Buckingham Palace in London.

Charles, who became king in September 2022 following the death of his mother Elizabeth II, was diagnosed with an unspecified cancer last month.

The 42-year-old princess has been recovering mainly at the home she shares with William and their three young children in Windsor, west of London, since leaving hospital on January 29.

The photos published by TMZ showed Kate wearing sunglasses while being driven by her mother in a car. The celebrity news site said the images were taken on Monday near Windsor Castle.

Social media has been alight with conspiracy theories over the princess's prolonged absence from the spotlight. Rather than suppressing rumours, Joe Little, managing editor of Majesty Magazine, said the photograph had "generated more speculation".

"It's a tricky situation because we're all entitled to our privacy when we are unwell," he told AFP.

"But when you are a member of the royal family that is quite complicated and difficult to maintain, there is naturally a huge amount of public interest."

Royal shortage

The illnesses of Charles and Catherine have given rise to a sense of uncertainty around the royal family.

William himself missed events to look after his family. He also pulled out of a recent memorial service for his late godfather King Constantine II of Greece over an unspecified "personal matter".

Charles's wife Queen Camilla, 76, has been the most visible senior royal, stepping in to cover many of her husband's public duties during his treatment.

She is now on a break until March 11, when she is expected to join William and other senior royals at the annual Commonwealth Day service at Westminster Abbey.

She is reported to be on holiday this week, effectively meaning all four of the most senior royals are out of action.

William, 41, was last seen in public on Thursday during a visit to a London synagogue, where he condemned the rise of anti-Semitism in Britain.

He also attended last month's BAFTA film awards ceremony in London.

Kate's last public appearance was on 25 December when the royals attended a Christmas Day church service -- around three weeks before she was admitted to hospital for abdominal surgery.

Royal officials refused to say what she was being treated for but said the condition was non-cancerous.

She spent almost two weeks in hospital and Kensington Palace said she was unlikely to return to public duties until after Easter on 31 March.

The princess, widely known as Kate, is one of the most popular members of the royal family.

She and William have taken on more royal duties since his younger brother Prince Harry and his wife Meghan left for the United States in 2020, and the king's brother Prince Andrew stepped back because of his friendship with the convicted sex offender Jeffrey Epstein.