The British Army posted the engagement on its official website, saying Catherine, who is married to the heir to the throne Prince William, will help review soldiers as part of the annual Trooping the Colour.

Kate, as she is fondly known, and William’s Kensington Palace office has not confirmed her appearance at the event.

Meanwhile, the king, who is currently being treated for cancer, is scheduled to review troops at the Trooping the Colour main event on June 15, according to the army website.

Charles held an in-person audience today with finance minister Jeremy Hunt ahead of the government’s official budget announcement 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 central London.

Kate was spotted in public yesterday for the first time since she underwent abdominal surgery in mid-January, according to photos published by US outlet TMZ.

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 the hospital on Jan 29.

The photos published by TMZ showed Kate wearing sunglasses while being driven by her mother in a car, with the celebrity news site saying they were taken yesterday near Windsor Castle.

The sighting comes as social media has been alight with conspiracy theories over the princess’s prolonged absence from the spotlight.