The 10th anniversary of the death of Princess Diana in a car crash in Paris is being marked with a memorial service in London and tributes across the UK.
Princes William and Harry will lead readings for their mother at the Guards' Chapel, near Buckingham Palace.
Guests including Lord Attenborough and Mario Testino are taking their places.
Harrods owner Mohamed Al Fayed, whose son Dodi died in the crash alongside the princess, laid flowers at a shrine he has built at the London store.
A two-minute silence was also held there.
Prince Charles and the Queen will be at the service at the Guards' Chapel, although Charles's second wife Camilla will not be attending.
Prime Minister Gordon Brown and Sir Elton John, who sang at Diana's funeral, will also pay their respects.
Similar events are to be held at venues across the UK, including Manchester, Bristol, Aberdeen and Cardiff.
The Royal Family, headed by the Queen, will be joined by another 100 family members at the hour-long Guards' Chapel service, which is due to begin at midday on Friday.
However, in a statement earlier this week Camilla, the Duchess of Cornwall, said her attendance "could divert attention from the purpose of the occasion".
She said she was grateful to her husband and the princes for supporting her decision not to be there.
William and Harry, along with Diana's brother, Earl Spencer, have been closely involved in organising the service, which will include some of their mother's favourite classical music, by composers Rachmaninov and Mozart.
There will be four hymns, concluding with Diana's favourite, I Vow To Thee, My Country, and a reading from her sister, Lady Sarah McCorquodale.
The service, conducted by the Reverend Patrick Irwin, will also include two prayers written by Archbishop of Canterbury Rowan Williams and an address will be given by the Bishop of London, the Right Reverend Dr Richard Chartres.
Former members of the princess's staff, all of the bridesmaids and page boys from her 1981 wedding, and over 110 representatives of charities and organisations with which she was associated are also on the guest list.
Sir Elton John - who famously performed a reworked version of Candle In The Wind at Diana's funeral - Sir Cliff Richard and Lord Attenborough are also expected.
Tony Blair, who was prime minister at the time of her death and famously paid tribute to her as the "People's Princess", is also due to attend.
A spokesman for Mr Al Fayed said the Harrods owner's daughter Camilla would attend the service, which he hoped would go "extraordinarily well".
Hundreds of people are also expected to attend the Manchester service - at 1630 BST on Friday - which will include readings, a blessing and music which was played at the princess's funeral.
Staff and representatives from charities and organisations supported by Diana - including Barnado's, the English National Ballet and the National Aids Trust - have been invited to tour her family home at Althorp, near Northampton.
Admirers of the late princess have already started tying flowers and cards to the gates of Kensington Palace - her former London residence - as they did in 1997 after her death.
Members of the public have also left bouquets and gifts outside Althorp, where Diana is buried, at the gate of Sandringham estate in Norfolk, where she was born, and near the Eternal Flame monument by the tunnel in Paris where she was killed.
Princess Diana died, aged 36, along with her companion Dodi Al Fayed, 42, and chauffeur Henri Paul, when the Mercedes they were in crashed in the Pont de l'Alma tunnel on 31 August 1997.
The princess's death provoked an unprecedented outpouring of national grief, with hundreds of thousands gathering to mourn outside Kensington Palace, where they left a sea of floral tributes.
Thousands more later lined the route of her funeral procession.
First published by www.bbc.co.uk|