However, some Twitter users hit out at the Duke who has faced some backlash in Britain following his and Meghan Markle's explosive sitdown interview with Oprah Winfrey.
One critic raged: "Can he do nothing private? Why does he have to have a spokesperson declare how he celebrates his mother?
"Again another example of how they just live for the fame & not the privacy they claim."
While another put: "Flowers laid, check. Press called, check. Not subtle, check."
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Prince Harry news: Harry and Meghan's explosive interview with Oprah Winfrey aired in the UK last Monday (Image: CBS)
Prince Harry is due back in the UK on July 1 when he and Prince William are scheduled to unveil a new statue in Diana's honour.