Prince William pays personal tribute to Queen Elizabeth II

(CBS News) Prince William shared a personal tribute to Queen Elizabeth II on Monday, just days before the central celebrations for her Diamond Jubilee.

The Duke of Cambridge, 29, posted a picture of himself and his grandmother on the Historypin website and wrote a message to go with it.

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The photo is from Dec. 15, 2006, during the Sovereign's Parade at Sandhurst Military Academy in Sandhurst, England. As the queen passed William (then 24) in a lineup of the academy's graduates, both are seen smiling.

"I felt especially proud to receive my commission as an officer in front of my grandmother, The Queen," the prince wrote in a post accompanying the photo. "She has been an incredible role model to me over the years, so it was very special to have her present for my graduation. I know it was also a memorable moment for my fellow officers to take part in the Parade in front of The Queen as Head of the Armed Forces."

William continued, "I remember The Queen's words as she addressed us from the tremendous parade ground at Sandhurst: 'You must be courageous yet selfless, leaders yet carers, confident yet considerate.' These qualities of selflessness and duty are values that The Queen has continuously demonstrated over the last 60 years and are qualities that remain very important to me."

Next weekend, four days of festivities are planned to mark the queen's Diamond Jubilee. Among the events planned for June 2-5 are a parade of boats down the River Thames and a concert at Buckingham Palace followed by fireworks.