It's a date that has been in the diaries of Prince William and Prince Harry for a long time – but original plans are being changed last minute.
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The guest list for next Thursday's big royal ceremony has been drastically reduced because of COVID-19 rules.
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Up until last week, Prince William and Prince Harry had wanted to invite around 100 of Diana's friends, ex-staff and supporters, Richard Kay reveals to the Mail Online.
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It now seems that only a handful of guests will attend, the Princes, the Duchess of Cambridge and some of Diana's relatives.
Guests that had been expected at the 1 July ceremony, have now been told that a new date will be fixed for September – COVID-19 permitting.
The Princes will reunite next week
Princess Diana's sons will reunite next week at the Sunken Garden at Kensington Palace on what would have been their mother's 60th birthday.
It will be the first time the brothers have reunited since the Duke of Edinburgh's funeral at St George's Chapel in Windsor in April.
Prince William and Kate were seen walking alongside Harry after the moving service.
The Duke and Duchess of Sussex moved to the US last year after stepping back from royal duties and welcomed their second child, Lilibet Diana Mountbatten-Windsor, on 4 June.
Harry is set to arrive in the UK imminently so that he can isolate for a minimum of five days, assuming he does the 'test to release' scheme. If not, he will need to isolate for ten days under UK government rules, as the United States is on the amber list.