The nuptials will draw most senior members of the royal family, including Eugenie's grandmother, Queen Elizabeth II, who will host a champagne luncheon for the newlyweds shortly after the ceremony.
Harry and Meghan are expected to attend, along with Prince William and his wife Kate, the Duchess of Cambridge. Their 5-year-old son, Prince George, will be a page boy, and Princess Charlotte, 3, will be one of six bridesmaids.
Eugenie, 28, is ninth in line to the British throne. She works in the art world. Her sister, Princess Beatrice, will be maid of honor. They are the daughters of Prince Andrew and Sarah Ferguson, who are divorced but enjoy an amicable relationship.
Eugenie and Brooksbank, 32, have dated for many years. He proposed to her in January during a trip to the Central American country of Nicaragua, choosing a romantic spot next to a lake and a volcano.
Eugenie told ITV, which will broadcast the hour-long service in Britain, that she was both excited and a bit on edge.
"It's nerve-wracking and a bit scary and all the things that come with getting married, but at the end of the day you get to marry the person you love," she said.
The couple has invited 1,200 members of the public to come onto the castle grounds for a closer glimpse of proceedings. They also plan to take a carriage ride through parts of Windsor just after the ceremony.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)