Prince Harry and Meghan Markle's wedding next May will "reflect their characters and personalities" and be a moment of "fun and joy", Kensington Palace says.
As palace aides announced more details of the big day, it was revealed that American Markle is to become a British citizen, and will be both baptised and confirmed ahead of the religious ceremony.
The royal family will pay for the wedding, including the church service, the music, the flowers and the reception, the palace said.
But the security costs for the high profile celebration will fall to the taxpayer.
The Queen will be there, as will the rest of the royal family, along with Ms Markle's parents Thomas Markle and Doria Ragland.
Prince George and Princess Charlotte are also expected to take on the roles of pageboy and bridesmaid. The palace revealed that Markle has met them on many occasions.
Kensington Palace is yet to confirm the exact date of the nuptials, who will be Harry's best man or Markle's bridesmaids, and how many guests will attend.
The Prince of Wales and the Duchess of Cornwall, who had their religious blessing in the same chapel in 2005, were joined by around 800 people.
Harry's communications secretary Jason Knauf said Windsor was a "very special place" for the prince, and that he and Markle had regularly spent time there together during their 16-month romance.
He said the couple were delighted to be holding the wedding in the castle's "beautiful grounds".
Knauf said the newly-engaged pair, who were grateful for the warm wishes they had received, "want the public to feel part of their day" - and are looking at ways to achieve that.
They will be putting their stamp on their wedding day, and are leading the arrangements.
Knauf said: "The wedding will reflect their characters and personalities as you would expect anyone's wedding to.
"It's a royal wedding and it will rise to that standard as well. But like the Duke and Duchess (of Cambridge) did, it will reflect who they are as a couple.
