King Charles will take part in Trooping the Colour amid his cancer treatment.
The 75-year-old monarch was diagnosed with cancer earlier this year, but he's expected to inspect soldiers from a carriage during the ceremony on June 15.
Charles - who recently returned to public-facing duties - will conduct the review seated in an Ascot landau carriage, rather than on horseback.
The monarch has carried out a series of public engagements over recent weeks, even though he is still receiving treatment for cancer.
Elsewhere, Catherine, Princess of Wales will miss next month's Colonel's Review, as she continues her own recovery from cancer.
The 42-year-old princess revealed in March that she was undergoing preventative chemotherapy and she has not taken part in public engagements since then.
The ceremonial military event is a dress rehearsal for the Trooping the Colour and is set to take place in London on June 8.
At the moment, it remains unclear as to whether the princess will attend Trooping the Colour alongside other members of the royal family.
Buckingham Palace announced in February that Charles had been diagnosed with cancer.
At the time, it was revealed that the monarch felt "positive" about his treatment and that he was keen to return to public duties as soon as possible.
The statement read: "During The King’s recent hospital procedure for benign prostate enlargement, a separate issue of concern was noted. Subsequent diagnostic tests have identified a form of cancer.
"His Majesty has today commenced a schedule of regular treatments, during which time he has been advised by doctors to postpone public-facing duties. Throughout this period, His Majesty will continue to undertake State business and official paperwork as usual.
"The King is grateful to his medical team for their swift intervention, which was made possible thanks to his recent hospital procedure.
"He remains wholly positive about his treatment and looks forward to returning to full public duty as soon as possible.
"His Majesty has chosen to share his diagnosis to prevent speculation and in the hope it may assist public understanding for all those around the world who are affected by cancer."
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