LONDON -- It will be a spring wedding on the glorious grounds of Windsor Castle for love-struck Prince Harry and Meghan Markle.

Royal officials -- thrilled with the international response to news of the couple's engagement, and the positive reaction to their first ever TV appearance -- revealed a few key details Tuesday but kept mum on others, such as who will be Harry's best man?

but the date has not been chosen, Harry's communications secretary, Jason Knauf, told a packed briefing at Buckingham Palace.

"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 before fielding questions about things like how many of Markle's rescue dogs would move to Britain with her.

Knauf said Harry's grandmother, Queen Elizabeth II, had given permission for the couple to wed at St. George's Chapel, the historic church on the Windsor Castle grounds that has long been a touchstone for royal rites of passage. He said the 91-year-old monarch will attend the wedding.

Windsor Castle, west of London, is one of the queen's favourite residences. St. George's, the 15th-century chapel where the couple will wed, is more intimate than Westminster Abbey, where Harry's older brother, William, married Kate Middleton in 2011.

Knauf said Windsor "is a very special place for Prince Harry," and that he and Markle have regularly spent time there since they began dating about a year and a half ago.

He said the wedding "will be a moment of fun and joy that will reflect the characters of the bride and groom."

The image-conscious royals also made clear in a statement that the royal family, not British taxpayers, will foot the bill for what is expected to be a grand extravaganza. The family will pay for the church service, the music, the flowers, the decorations and the reception that follows.

Harry's press team is keeping some details private for the moment -- perhaps because final decisions have not been made.

It's also not clear who will be Harry's best man, though older brother William would seem to be a strong contender.

Knauf also would not say whether Archbishop of Canterbury Justin Welby will preside over the service. And as for what titles will be given to Harry and Markle, that will be decided by the queen and revealed at a later date.

The palace was ready to answer some delicate questions about the 36-year-old Markle's move to Britain and her taking up a senior role in the royal family, sometimes called "the firm."

Knauf said she will comply with all immigration requirements and will become a British citizen, a process that may take several years, and will retain her U.S. citizenship throughout the process.

He did not say whether she would drop her U.S. citizenship at some point.

Asked about her religion, Knauf said Markle is a Protestant who will be baptized in the Church of England, which is headed by the queen in a largely ceremonial role.

Markle's personal belongings are being shipped from Canada, where she has lived for seven years while performing in the TV legal drama "Suits," to Nottingham Cottage, where she and Harry will live. The cottage is located on the grounds of Kensington Palace in central London.

She has already brought one of her two rescue pups, Guy, but the other -- Bogart -- is being left behind and will reside permanently with "good friends," Knauf said.

The union of the 33-year-old prince and Markle, an accomplished TV actress in her own right, represents a blending of Hollywood and royalty that is expected to draw an international audience -- officials said it is a safe assumption that the service will be televised.

The couple will carry out their first official engagement on Friday, visiting a youth charity and a World AIDS Day event in Nottingham in central England. For Markle, it will be a first taste of life as a working royal.

Markle's divorced status would once have barred her from marrying the prince in church. Harry's father Prince Charles, who is heir to the British throne, married his wife Camilla in a low-key civil ceremony in 2005 because both bride and groom were divorced.

Camilla said Tuesday she was "delighted" her stepson was marrying the U.S. actress.

"America's loss is our gain," she said.

Newspapers hailed news of the engagement as a breath of fresh air and symbol of a modernizing monarchy.

The Daily Telegraph said in an editorial: "A divorced, mixed-race Hollywood actress who attended a Roman Catholic school is to marry the son of the next king. Such a sentence could simply not have been written a generation ago."