Here are brief profiles of the supporting cast at the wedding of Prince Harry and Meghan Markle:
PRINCE WILLIAM, DUKE OF CAMBRIDGE
Best man, 35
Older brother William returns the favour Harry performed at his wedding in 2011.
William, who is in line to become king after their father Prince Charles, has given up his job as an air ambulance helicopter pilot to become a full-time royal. He is now a father of three after the arrival of Prince Louis on April 23.
Mother of the bride, 61
A social worker and a yoga instructor, Meghan calls her mother a "free spirit".
She has a master's degree in social work and ran the 2017 Los Angeles marathon. In the absence of her ex-husband Thomas Markle, who is recovering from a heart operation, she is thought the most likely to walk her daughter down the aisle.
DAVID CONNER, DEAN OF WINDSOR
Ceremony leader, 71
Conner is the senior cleric at St. George's Chapel and will therefore conduct the service.
He has been the dean since 1998 and was also bishop to the armed forces during Harry's time in the army. He was formerly the vicar of the Cambridge University church.
JUSTIN WELBY, ARCHBISHOP OF CANTERBURY
Spiritual leader of the Church of England, 62
The Anglican Communion's most senior bishop will officiate as the couple make their marriage vows. A former oil executive, Welby baptised Markle after her engagement. He went to Eton College, as did Harry.
MICHAEL CURRY, PRIMATE OF THE EPISCOPAL CHURCH
Sermon reader, 65
The head of the Anglican church in the United States has been invited to give the address, the main speech during the wedding. The charismatic African-American from Chicago is a lively, animated preacher in the US tradition and could be the star turn in a setting more used to rigid formality. Markle's father is an Episcopalian.
QUEEN ELIZABETH II
Grandmother of the groom, 92
Her Majesty has reigned since 1952.
A steadfast monarch in a changing world, Queen Elizabeth has been a figure of constancy who has overseen post-war Britain into the new millennium. She is hosting the reception afterwards in Windsor Castle's St. George's Hall.
PRINCE PHILIP, DUKE OF EDINBURGH
Grandfather of the groom, 96
Prince Philip has been at the Queen's side since they wed in 1947. A naval officer, he served in World War II and witnessed the Japanese surrender. He retired from royal duties in 2017. The duke is renowned for his off-the-cuff remarks. He left hospital on April 13 after a hip replacement but is expected to attend at least some of the day, having been seen outdoors since the operation.
PRINCE CHARLES, PRINCE OF WALES
Father of the groom, 69
The heir to the throne has spent a lifetime preparing to be king.
His "fairytale" marriage to Diana, princess of Wales disintegrated. Outspoken on the environment and architecture, he also heads the wide-ranging Prince's Trust charity. He is hosting the evening wedding reception at Frogmore House in Windsor.
CAMILLA, DUCHESS OF CORNWALL
Stepmother of the groom, 70
Charles's former mistress married the heir to the throne in 2005.
She uses one of her husband's lesser titles and has kept a low profile accompanying him on visits.
Camilla is set to become princess consort upon Charles' accession to the throne.
-- Princess Charlotte of Cambridge, 3: Harry's niece
-- Florence van Cutsem, 3: Harry's goddaughter
-- Zalie Warren, 2: Harry's goddaughter
-- Rylan Litt, 7: Markle's goddaughter
-- Remi Litt, 6: Markle's goddaughter
-- Ivy Mulroney, 4: daughter of Markle's friend Jessica Mulroney
Florence van Cutsem's father Nicholas is a lifelong friend of Harry and William. His brother Edward was a page boy at Charles and Diana's wedding.
Zalie Warren is the granddaughter of Queen Elizabeth's bloodstock and racing adviser John Warren.
Benita Litt is a close friend of Markle, who is godmother to her two daughters.
Ivy Mulroney's stylist mother Jessica runs a bridal store in Toronto, where Markle filmed "Suits", and is said to have helped choose the wedding gown. She is married to Ben Mulroney, son of former Canadian prime minister Brian Mulroney.
-- Prince George of Cambridge, 4: Harry's nephew
-- Jasper Dyer, 6: Harry's godson
-- Brian Mulroney, 7: son of Jessica Mulroney
-- John Mulroney, 7: Brian's twin brother
Jasper Dyer's father is Mark Dyer, a former equerry to Charles who was entrusted to keep an eye on Harry after Diana's death. The pair travelled together during Harry's gap year.
Britain's Prince William, seen here with Kate and his baby son Louis, will be best man at his brother Harry's wedding
Meghan Markle is likely to be walked down the aisle with her mother Doria Ragland, seen here to her left
David Conner, seen here with the Queen, has been the dean of Windsor since 1998
As the spiritual head of the Church of England, Archbishop of Canterbury Justin Welby will officiate over their vows
Queen Elizabeth has overseen post-war Britain into the new millennium
Prince Philip may not attend the entire wedding day after recently undergoing a hip replacement operation
Prince Charles has spent a lifetime preparing to be king after his long-serving mother Queen Elizabeth
Camilla, Duchess of Cornwall, Prince Charles's former mistress, is set to become princess consort on his accession to the throne
Princess Charlotte of Cambridge, 3, will be one of six bridesmaids when her uncle Prince Harry gets married on Saturday
Prince George, seen here on his first day of school in London, will be one of four pageboys when his uncle Harry gets married on Saturday