Taking to Instagram, the 30-year-old posted three beautiful images, along with the caption: "Happy Birthday to HRH The Duke of Edinburgh. I found a couple of classic photographs of Grandpa and I on Christmas Day and Trooping the Colour a few years ago," she wrote.
In one of the photos, Prince Philip, who turns 98, can be seen patting his granddaughter of the head as they attend church on Christmas Day.
In another, a young Eugenie is standing alongside the Duke and The Queen on the balcony of Buckingham Palace.
Prince Philip was born on June 10 1921 and has been married to the Queen for more than 71 years.
He is the longest serving consort in British history.
Last month, His Royal Highness was spotted in good form, laughing and joking with other members of the royal family at Lady Gabriella Windsor’s wedding.
These days, Philip mostly stays at Wood Farm on the Sandringham estate in Norfolk, where he busies himself by reading, painting, meeting friends and staying active.
He still enjoys carriage-driving and was seen at the reins at the Windsor Horse Show in May.
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