The Queen faced the difficult task of picking just 30 guests to attend Prince Philip's funeral due to Covid restrictions, from a list that was originally about 800 people long.
All of the Duke of Edinburgh's children and grandchildren will attend, with Prince Harry flying back from the US to say his final goodbyes.
One of the few remaining spots has been given to his dear friend Penny Brabourne, the Countess Mountbatten of Burma, with whom the prince shared "decades of affection".
Penny, 67, is married to Earl Mountbatten, Norton Knatchbull, who is the grandson of Philip's much-loved uncle, the 1st Earl Mountbatten.
She became close to the Duke and the Queen after the death of her five-year-old daughter, Leonora, from liver cancer in the early 90s.
Understanding loss better than most due to a childhood filled with tragedy, Philip reported began inviting Penny on carriage rides.
They shared a love of the outdoors and the Duke taught her how to carriage ride in 1994.
When he moved to Sandringham after his retirement in 2017, Penny was a regular guest at his Wood Farm cottage.
Staff nicknamed her "and also" as Philip also insisted that she was added onto the guestlist for all events.
They enjoyed each others company and would regularly attend the Royal Windsor Horse Show together.
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A source told Grazia : "Penny and the Duke of Edinburgh shared decades of affection. Her presence at the funeral among only thirty attendees is exactly what the late Duke would have wanted, and the entire family will be pleased to have her among them on the sombre occasion."
Prince Charles is good friends with Penny's husband having attended Gordonstoun together, and the heir to the throne was best man at their wedding in 1979.
Prince Philip was involved in the preparations for his funeral, and experts say Covid means he's got his final wish in having a "no fuss" send off.
Well-wishers are being asked to stay away and to watch the service, which will take place at Windsor's St George's Chapel, on TV.
The Duke's coffin will be carried on a specially modified Land Rover he helped to design.
All mourners will be required to wear face masks and must stay at least two metres apart from anyone not in the same household.
As well as members of the royal family, the Queen has invited three of Prince Philip's relatives from Germany.