Early next month Britain will honour the queen's Platinum Jubilee with four days of pageantry and celebration. Buckingham Palace has previously said she intends to attend a number of different events.
Last week she made a surprise appearance at the opening ceremony for a new rail line in London and the week before attended a horse show on the grounds of her Windsor Castle.
Earlier in May she missed her annual address to parliament, with the palace citing episodic mobility issues. Until recently, she had not been seen often in public following a night in hospital last October for an unspecified illness.
