A huge world audience is set to watch the glittering wedding of Prince Harry and Meghan Markle in a chapel within the ancient walls of Windsor Castle, home to the royal family for nearly 1000 years.
Markle has confirmed she will walk down the aisle without her father, putting an end to days of speculation that has marred the build-up to Britain's biggest social event of the year.
In the town of Windsor during the build-up to the wedding, crowds of wellwishers have mingled with tourists and swarms of television crews under swathes of red, white and blue Union flags.
Harry, Queen Elizabeth's grandson, and US actress Markle, a star of the TV drama Suits, will tie the knot on Saturday in a royal extravaganza at the castle's 15th-century St George's Chapel.
Markle's father, Thomas, had been due to walk his daughter down the aisle in front of a congregation of senior royals, celebrities, friends of the couple and a TV audience of hundreds of millions.
But the former lighting director for TV soaps and sitcoms gave a series of contradictory statements about whether he would be there, with the Los Angeles-based celebrity website TMZ.com saying he had undergone heart surgery on Wednesday.
"Sadly, my father will not be attending our wedding. I have always cared for my father and hope he can be given the space he needs to focus on his health," Meghan Markle, 36, said in a statement on Thursday.
"Please know how much Harry and I look forward to sharing our special day with you on Saturday."
The wedding celebrations, forecast to play out under sunshine and blue skies, will be a sumptuous show of British pageantry.
Supporters hope the union of one of the most popular royals and a glamorous American actor, a divorcee with a white father and an African-American mother, will reinvigorate the monarchy.
Markle's mother Doria Ragland, a yoga instructor and social worker who is divorced from Thomas Markle, will spend the night before the wedding with her daughter in the five star Cliveden House hotel and accompany her to the chapel.
Royal commentators have speculated Ragland will walk her daughter down the aisle.
After the hour-long ceremony, the couple will take part in a procession through Windsor's ancient streets on a 19th Century Ascot Landau carriage pulled by four Windsor Grey horses.
Police are expecting more than 100,000 people to throng the streets outside the castle, the Queen's home west of London and have said there would be tight security for the event.
Queen Elizabeth, the world's longest reigning current monarch, is deeply respected and popular in Britain. Harry, 33, the younger son of the late Princess Diana, has himself always been a very popular member of the royals.
In Windsor sales of everything from flags and biscuits to tea towels emblazoned with the couple's pictures have been brisk. Some royal fans have slept on the street since Tuesday to catch a glimpse of the newlyweds on Saturday.
"The atmosphere at the moment is wonderful," said Sandra Atkinson, a 54-year-old shop assistant.
"We've sold out of all our mugs, all our tea towels. It's been wonderful for business. We were expecting the Americans to come in, and they have come in."