The British Army has swiftly removed a claim on its website that Catherine, the Princess of Wales, will attend a Trooping the Colour ceremony in June.
That engagement would have been the first appearance announced for the 42-year-old royal since she underwent abdominal surgery.
The announcement by the Ministry of Defence caused confusion, because Prince William and Kate's office, Kensington Palace, had not confirmed any scheduled public events for Kate.
The BBC reported that the Army did not seek approval from the palace before publishing the page, which had a picture of Kate and copy stating she would be reviewing troops on 8 June.
Kate has been out of the public eye since January, when palace officials announced that she was admitted to a private London hospital for planned surgery.
They didn't provide more details, but said that she wouldn't return to public duties until after Easter.
Kate holds the title of Colonel of the Irish Guards.
The ceremony's events, annual highlights in the royal calendar, are birthday parades to honour the reigning monarch and usually draw huge crowds.
The tradition dates back more than 260 years.
The spectacle is held at central London's Horse Guards and along The Mall, the promenade outside Buckingham Palace.
The royal family has been under media scrutiny in recent weeks, because both Kate and King Charles III can't carry out their usual public duties because of health problems.
Royal officials say that Charles is undergoing treatment for an unspecified form of cancer, which was discovered during treatment for an enlarged prostate.
The monarch has cancelled all his public engagements while he receives treatment.
Kate was discharged from hospital on January 29 after two weeks for her undisclosed condition.
Palace officials have said she wished her personal medical information to remain private.
Speculation about her health mounted last week when William at the last minute pulled out from a memorial service for his godfather, the late King Constantine of Greece, because of what officials called a "personal matter."
Palace officials didn't elaborate, but reiterated that Kate continues to do well in her recovery.
- With Associated Press
