Windsor - Flanked by page boys and bridesmaids, American actress Meghan Markle walked down the aisle of the 15th Century chapel in Windsor Castle where she will marry Prince Harry in a dazzling display of British pomp and pageantry.
After entering St George's Chapel unescorted, Markle - wearing a dress designed by Clare Waight Keller - made her way towards the Quire, halfway down the church where Prince Charles will walk her to his son, Harry.
The long-sleeved dress with a boat neck had been eagerly anticipated by royal fans around the world for months.
Waight Keller became the first female artistic director at famed French fashion brand Givenchy last year.
White roses, favourite flowers of Harry's late mother Princess Diana, adorned the chapel. Markle's mother, Doria Ragland, 61, appeared tearful.
Prince Harry, dressed in a military frock coat uniform, and his brother, best man Prince William, waited for Markle at the altar.
Tens of thousands of fans lined the route Markle took towards the castle, waving British flags and cheering as the Rolls-Royce limousine drove past with the bride and her mother.
Air traffic controllers for the nearby Heathrow Airport, one of the world's busiest, said the air space over Windsor was being closed for 15 minutes before the ceremony.
Hours before, Queen Elizabeth bestowed the title of Duke of Sussex on her grandson, a step that means the American actress, star of the TV drama "Suits", will become a duchess when she marries Harry.
Under clear skies and glorious sunshine, a military band in scarlet uniforms and bearskin hats entertained excited fans gathered behind barriers. Police armed with semi-automatic rifles patrolling streets and watching from rooftops.
"It’s absolutely incredible. The atmosphere here is just going to be crazy when Meghan turns up. I’m so pleased to be here," said Charlotte Field, 21, one of 1,200 people invited into the grounds of the castle for the wedding.
A host of guests were present. U.S. media mogul Oprah Winfrey and actor George Clooney and his wife Amal were joined by former soccer star David Beckham, his fashion designer wife Victoria and James Corden, the British host of the American TV chat show "The Late Late Show".
Other guests included tennis ace Serena Williams, the siblings of Harry's late mother Princess Diana, singer Elton John, who sang at Diana's 1997 funeral, British actor Idris Elba, and two of Harry's ex-girlfriends.