The portrait, taken earlier this month, showed the queen wearing the same dress which she chose for a service of thanksgiving to mark their diamond wedding anniversary held at the Abbey where they were married.
She is also wearing a “Scarab” brooch in yellow gold, carved ruby and diamond which Philip gave her in 1966.
Elizabeth has been married for far longer than any other royal, and the newly-released picture showed the couple framed by Thomas Gainsborough’s 1781 portraits of George III and Queen Charlotte, who were married for 57 years - the second longest royal marriage.
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