The Duke of Cambridge also met with England's women's soccer team.
Harry describes his mother as 'one of the naughtiest parents.'
Kate Middleton, Princess Charlotte and Prince George also attended the private memorial service on Saturday in England.
ET has insider details on how the royals will remember Diana on what would've been her 56th birthday.
She will also be present at the rededication of Princess Diana's grave this upcoming Saturday.
Prince William, Prince Harry and Kate Middleton to Rededicate Princess Diana's Grave on Her Birthday
The newly married 33-year-old was photographed in London on Tuesday after her month-long getaway with her new husband, James Matthews.
Looks like the British monarchy is getting a facelift.
The royal opened up in a new tell-all profile with 'Newsweek.'
In honor of the royal's birthday, ET breaks down all the times he made us laugh, smile and shed a tear.
The Duchess of Cambridge stepped out in a gorgeous white mini dress by Alexander McQueen.
The 34-year-old royal hugged a survivor affected by the deadly Grenfell Tower fire in London.
He visited victims of the Grenfell Tower fire in London on Friday.
Plus, see how Prince George stole the show at Queen Elizabeth's annual birthday event!
