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
Meghan calls her mother, a social worker and yoga instructor, a "free spirit".
She has a master's degree in social work and ran the 2017 Los Angeles marathon. She arrived a few days before the wedding, meeting Harry's father Prince Charles and grandmother Queen Elizabeth II.
Her ex-husband Thomas Markle, Meghan's father, is not attending after undergoing an emergency heart operation in the days leading up to the wedding.
PRINCE CHARLES, PRINCE OF WALES
Father of the groom, 69
The heir to the throne will walk Meghan down the aisle after her father pulled out.
No stranger to controversy himself, his "fairytale" marriage to Harry's mother Diana disintegrated in public scandal, before her death in a car crash in 1997. He remarried in 2005.
Outspoken on the environment and architecture, he heads the wide-ranging Prince's Trust charity while he prepares to become king. He is hosting the evening wedding reception at Frogmore House in Windsor.
DAVID CONNER, DEAN OF WINDSOR
Ceremony leader, 71
As senior cleric at St. George's Chapel, he will 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 baptised Markle after her engagement and will officiate as the couple make their marriage vows. A former oil executive, 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 will 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.
QUEEN ELIZABETH II
Grandmother of the groom, 92
Her Majesty has reigned since 1952.
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 underwent a planned hip replacement on April 4, but officials say he will attend the wedding.
CAMILLA, DUCHESS OF CORNWALL
Stepmother of the groom, 70
Charles's former mistress, she married the heir 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.
Several of Meghan's former co-stars from the US television series "Suits" have been photographed in Britain ahead of the wedding, including Patrick J. Adams, who played her on-screen husband.
Stylist Jessica Mulroney was also photographed in London. She runs a bridal store in Toronto, where Markle filmed "Suits", and is said to have helped choose the wedding gown. Her husband Ben Mulroney is son of former Canadian prime minister Brian Mulroney.
-- 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.
-- 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.