London, UK - Princess Anne, sister of King Charles III, was in the hospital on Monday with "minor injuries and concussion" after apparently being injured by a horse.

The incident took place at Anne's country home, Gatcombe Park, in southwest England, late on Sunday, Buckingham Palace said in a statement.

It is the latest health issue to hit the British royal family this year, after both Charles and his daughter-in-law Catherine, Princess of Wales, were diagnosed with cancer.

"Her Royal Highness remains in Southmead Hospital, Bristol, as a precautionary measure for observation and is expected to make a full and swift recovery," the statement added.

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"The king has been kept closely informed and joins the whole royal family in sending his fondest love and well-wishes to the princess for a speedy recovery."

The 73-year-old royal, a keen horsewoman who competed at the 1976 Montreal Olympics, will remain at the hospital "unless or until her medical team advise otherwise".

The palace did not give details of the incident, but sources in the princess's medical team said her head injuries were consistent with an impact from a horse's head or legs.

Anne's husband, Tim Laurence, was at Gatcombe Park when the incident occurred and accompanied her to the hospital, said the palace. Her daughter Zara Tindall and son Peter Phillips were also on the estate at the time.

The grounds of Gatcombe Park are renowned for hosting the Festival of British Eventing every year, which attracts the world's best equestrian stars.

The princess is one of a dwindling number of working royals since the death of her mother, Queen Elizabeth II, in September 2022 and the departure of Charles's younger son, Prince Harry, and his wife, Meghan, to the US two years earlier.

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She has taken on extra engagements as Charles and Kate receive treatment and was recently seen at events for the 80th anniversary of the D-Day landings in northern France.

But her schedule for the week ahead will be postponed, said Buckingham Palace, including her planned attendance at Tuesday's state banquet for the emperor and empress of Japan. She had also been due to visit Canada.

The king has made a limited return to public duties and will host the Japanese royals when their state visit begins on Tuesday.

Catherine earlier this month tentatively returned to public life, attending a military parade in London to mark the king's official birthday and all eyes will be on Tuesday's banquet to see if she attends.