Prince Harry is to marry actress Meghan Markle.
Here's our lowdown on the royal wedding, announced today by Prince Charles:
Q: Where will the wedding take place?
A: It has not yet been announced. St George's Chapel at Windsor Castle is a good bet. It is smaller than Westminster Abbey and St Paul's Cathedral, but still grand enough for a high-profile royal wedding.
Q: Who will foot the bill?
A: For the Duke and Duchess of Cambridge's wedding, the costs including the church service, music, flowers, decorations, reception and honeymoon were split between the Queen, the Prince of Wales and Kate Middleton's millionaire parents.
But the taxpayer picked up the bill for security at the event, including the 5,000 police officers, and the clear-up operation on the streets afterwards, with reports suggesting the total cost to the taxpayer came to between £10 million and £20 million.
Q: Will the wedding day be a public holiday?
It will be up to the Government to decide whether to give Britons the day off.
An extra one-off bank holiday was added for William and Kate's nuptials but William is a future king, whereas Harry is now only fifth in line to the throne.
Q: When will the wedding be and what day of the week?
Royals usually have a short engagement so a spring wedding is likely. Royal weddings are traditionally during the week rather than at the weekend. William and Kate wed on a Friday and the Queen on a Thursday.
Q: What uniform will Prince Harry wear?
A: It is likely to relate to his most senior military appointment. Harry was an Army Captain in the Household Cavalry's Blue and Royals.
But he also has two additional honorary RAF and Navy uniforms, because he was appointed Honorary Air Commandant of RAF Honington and Commodore-in-Chief of small ships and diving.
He could be made an Army Colonel by the Queen ahead of his wedding and so therefore would wear the accompanying uniform instead.
William was told by his grandmother that he had to wear a red Guards' uniform on his wedding day because of his honorary title as Royal Colonel of the Irish Guards.
At the moment, Harry is likely to be in his Blues and Royals officer's uniform in Dismounted Review Order, which is navy blue with gold wire shoulder chords, ornamental gold braiding and red and gold cuffs, and which he wore to William and Kate's wedding
Q: Will Harry wear a blue sash like William?
A: He will not wear a blue sash across his uniform because he is not yet a member of the Order of the Garter.
But he will wear his Army Air Corps wings above his Queen's Golden Jubilee and Queen's Diamond Jubilee medals, and his Afghanistan campaign medals.
Q: Will American Meghan Markle become a British citizen?
A: Perhaps, but not necessarily. When Canadian Autumn Phillips married the Queen's grandson Peter Phillips, she said: "I'm happy being Canadian and I'm proud of where I come from. So I'll keep my passport."
Their children, Savannah and Isla Phillips, are said to hold dual British and Canadian citizenship, which would pave the way for dual citizenship for any children Harry and his bride might have.
Q: Will Ms Markle have to get a visa?
A: Technically yes. The rule is that all non-European nationals must obtain a visa if they want to come to the UK in order to marry.
Ms Markle could apply for a Family Visa if she wants to live with fiance Harry in the UK for more than six months.
Fees range from £993 to £1,583. Decisions by the Home Office can be made on the same day via the premium service or sometimes take up to 12 weeks. There is unlikely to be any hold-up for the future HRH.
Q: Will the bride have to be baptised or confirmed for a church wedding, if she has not been already?
A: No, you are not required to have been christened, be a regular churchgoer, or be confirmed to marry in a church.
Kate, who was baptised as a child, was confirmed shortly before her wedding to William. But William is a future king who will one day be Supreme Governor of the Church of England.
Q: How was the news announced?
Here is the announcement of Prince Harry and Meghan Markle's engagement
HIS ROYAL HIGHNESS PRINCE HENRY OF WALES AND MS. MEGHAN MARKLE ARE ENGAGED TO BE MARRIED
His Royal Highness The Prince of Wales is delighted to announce the engagement of Prince Harry to Ms. Meghan Markle.
The wedding will take place in Spring 2018. Further details about the wedding day will be announced in due course.
His Royal Highness and Ms. Markle became engaged in London earlier this month. PrinceHarry has informed Her Majesty The Queen and other close members of his family. Prince Harry has also sought and received the blessing of Ms. Markle's parents.
The couple will live in Nottingham Cottage at Kensington Palace.