Prince Harry and Meghan Markle will marry at St George's Chapel, Windsor Castle, in May, Kensington Palace says.
The Royal Family will pay for the wedding, including the service, music, flowers and reception - the date will be announced later.
Ms Markle, 36, a Protestant, will be baptised into the Church of England and confirmed before the wedding.
A spokesman for the prince said the pair would make sure the wedding "reflects who they are as a couple".
Jason Knauf said Prince Harry, 33, and Ms Markle were "leading the planning process for all aspects of the wedding" and were working through ideas on how members of the public could "feel part of the celebrations".
"This wedding, like all weddings, will be a moment of fun and joy that will reflect the characters of the bride and groom," he added.
Mr Knauf described Windsor as a "very special place" for the couple, saying they had spent time there together since meeting in July 2016.
He also revealed that the American actress intends to become a British citizen and will work towards it in the coming years.
St George's Chapel was the venue for a service of prayer and dedication after Harry's father, the Prince of Wales, married the Duchess of Cornwall at the Windsor Guildhall in 2005.
It was also chosen for the wedding of Harry's cousin, Peter Phillips, and Autumn Kelly in 2008, and the Earl and Countess of Wessex in 1999.
Harry, who is fifth in line to the throne, and Ms Markle announced their engagement on Monday.
Mr Knauf said it was "an incredibly happy day" for the couple and they were "overwhelmed by support from the UK and around the world".
Bogart left behind
Their 16-month relationship began when they met on a blind date in London arranged by a mutual friend.
The couple gave their first joint TV interview to the BBC's Mishal Husain on Monday - revealing the proposal came as they made roast chicken at home earlier this month.
They also discussed Ms Markle's pet dogs and Mr Knauf revealed that while one of them, Guy, was legally allowed to stay with her in the UK, the other, Bogart, would not be joining her.
The prince and Ms Markle will carry out their first official engagement together in Nottingham on Friday.
They will go on a walkabout and visit the Nottingham Contemporary which is hosting a Terrence Higgins Trust World Aids Day charity fair, and Nottingham Academy to meet head teachers.
Their spokesman said Ms Markle would not be continuing her work on gender with the United Nations or with other organisations, and instead would start new charity work as a full-time royal.
She is to become the fourth patron of the Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry.
Speaking during a visit to the Foundling Museum in London on Tuesday, the Duchess of Cambridge said both she and Prince William hoped the couple "enjoy this happy moment".
St George's Chapel has, we're told, become a "special place" for the couple. It is also a place of many happy childhood memories for Prince Harry.
It is a more intimate and private venue than Westminster Abbey or St Paul's Cathedral. But it also is grand enough to ensure this feels like a royal wedding.
The couple are currently working on plans to include the public in some way on their wedding day.
It will be a traditional wedding but it will reflect the character of the royal groom and his American bride. It will almost certainly be televised.
The best man? The bridesmaids? A new royal title? All for another day. But the couple begin the public side of their royal life together with a visit to Nottingham on Friday.
We were told Meghan Markle now wants to "get to know the UK".
The couple announced plans for a spring wedding on Monday, but by choosing May, have avoided a potential clash with the birth of the Duchess of Cambridge's third child and the Queen's appearance at the Commonwealth Heads of Government Meeting in London and Windsor - both of which are in April.
Downing Street has said there are no plans for a bank holiday to mark the wedding, after the possibility was mooted on social media.
Ms Markle was previously married, but the Church of England agreed in 2002 that divorced people would be allowed to remarry in church.