Queen Elizabeth's cousin Princess Alexandra has cancelled her royal engagements "for the foreseeable future".
The Honourable Lady Ogilvy - who is the sister of the Duke of Kent - is suffering from polymyalgia rheumatic, a debilitating type of arthritis, and hasn't been spotted in public this year due to the condition.
A Palace spokeswoman explained: "Her Royal Highness had a viral infection at the end of last year and was advised to rest. We do not know when she will next appear in public."
However, the 76-year-old princess is thought to be keen to get back to duty and is said to be in "good spirits".
She is said to be taking steroids to control the condition, which can cause blindness in some cases and also lead to stiffness of the joints as well as a swollen face.
Alexandra undertook 110 royal engagements last year, but her last occasion on royal duty came in December 20, 2012, when she appeared at St Paul's Cathedral to mark the 600th anniversary of the University of St Andrews.
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