In the meantime, Harry and his bride-to-be will tour the UK together so she can get to know the country and its people, beginning with a visit to Nottingham on Friday, a spokesman for Kensington Palace said at a media briefing on Tuesday afternoon.

In a nod to the legacy of Harry's mother, Princess Diana, the Nottingham visit is in support of HIV/AIDS charities.

WATCH: How it happened: Prince Harry's proposal

The palace also dropped another hint that one of the couple's first overseas trips together will be to the Invictus Games in Sydney in October, though official plans have yet to be announced.

The wedding will take place at St George's Chapel at Windsor Castle in May 2018 and the royal family will pay for the core costs such as the service, the music, the flowers and the reception.

Ms Markle, who is a Protestant, will be baptised and confirmed into the Church of England before the wedding. She will also apply for British citizenship, though the length of the process means she will still be a US citizen for the wedding.

Communications secretary to the prince Jason Knauf said the couple were "extremely grateful for the warm public response following yesterday's announcement of their engagement. In a happy moment in their lives, it means a great deal to them that so many people throughout the UK, the Commonwealth, and around the world are celebrating with them."

He said Windsor was a "very special place" for the couple as they had regularly spent time there over the last year and a half.

"Prince Harry and Ms Markle are delighted that the beautiful grounds of Windsor Castle will be where they begin their lives together as a married couple," he said.

They required, and were given, permission by the Queen to use the venue, which is where Harry was christened.

The Gothic chapel dates back to the 16th century and has hosted many royal weddings - as well as the 2005 blessing service for Charles and Camilla which followed their civil ceremony.

It also holds the tombs of 10 monarchs including Henry VIII and Harry's great-grandmother, and is the planned burial site for the Queen.

The couple want the day to be a "special celebratory moment for friends and family" and a "moment of fun and joy that will reflect the characters of the bride and groom," Mr Knauf said.

The chapel holds 800 people, compared to Westminster Abbey's 2000, but Mr Knauf said "it's a royal wedding and they will rise to that standard".

"They want the day to be shaped so as to allow members of the public to feel part of the celebrations too," he said.

Mr Knauf did not give details of Ms Markle's visa status, but said she will be "compliant with all immigration requirements at all times". She intends to have UK citizenship but the process takes a number of years. He didn't comment on whether she would retain her US citizenship.

Ms Markle, who is a Protestant though she went to a Catholic high school, will be getting baptised and confirmed in the Church of England for the wedding.

She and Harry are putting together a plan for a tour of the UK in advance of the wedding.

"She wants to get around the country and meet people," Mr Knauf said.

Ms Markle will end her current charitable work and start with a clean slate after the wedding as the fourth patron of the Royal Foundation, the charity run by Harry, William and Kate that includes the Invictus Games as well as mental health and wildlife arms.

Ms Markle wants to spend her time learning about the UK's towns and cities, but she also wants to focus on travelling around the Commonwealth.

In an interview on Monday she said she was excited about "being able to go around to the Commonwealth".

Mr Knauf would not comment on plans for the Invictus Games in Sydney next year, but it is a safe bet that Harry will be there, and very likely his wife will come with him.

Ms Markle's belongings are in transit to Kensington Palace in London, where the couple will set up their home in the palace's 'Nottingham Cottage'. However she plans a few trips in the next few months to visit friends and family before settling down there in advance of the wedding.

At the briefing, several royal reporters asked about Mrs Markle's rescue dogs, Bogart and Guy.

Mr Knauf said the beagle, Guy, will live with the couple at Kensington and is already in the UK but Bogart has a new home with a "very good friend of Ms Markle". He declined to say where Guy was currently living, noting "I am protecting the privacy of a beagle now".

Mr Knauf said it was too early to comment on many aspects of the wedding, as the couple were still planning it.

He said he was "looking forward to having lots of conversations about flowers".