Upon the Prince's arrival at the cemetery there was a picture set out of his mother laying a wreath at the same location 20 years earlier. William took a moment to view the black-and-white photo, which showed Diana wearing a navy coat as she paid her respects on February 7, 1995, before signing the book of condolences on the table.
Often keeping the thoughts of his mother private, William opened up about his grief last year after becoming the royal patron of the Child Bereavement Charity.
"Never being able to say the word 'mommy' again in your life sounds like a small thing," he said. "However, for many, including me, it's now really just a word — hollow and evoking only memories."
The Duke took time to tour the cemetery before following in his mother's footsteps and placing his own wreath at the memorial. He accompanied the arrangement with his own heartfelt message. "May we never forget all those who paid the ultimate sacrifice for our freedom," he wrote.
Later that day, the 32-year-old had a more lighthearted engagement in which he helped launch the Innovation is GREAT campaign in the Tokyo district of Roppongi Hills. He then donned a traditional Japanese Happi coat and took part in a sake barrel breaking ceremony at Mori Academy. The father of Prince George then spoke about some of the dream jobs he had as a child.
"When I was younger, I dreamt of being an astronaut," he said. "But I also thought that I was going to be a policeman one day, as a very small boy." And showing off his humorous side, the Prince added, "I've always wanted to say I'd be something like a fire breather. But that's far too alternative. So sadly, just a policeman for me."
The future king arrived in Tokyo on Thursday as part of a weeklong tour through Japan and China, a first for the royal. Also on the royal itinerary are visits to Beijing and Shanghai, where he will be highlighting British links with Japan and China and addressing issues such innovation, trade and creativity.