Princess Eugenie is to marry her long-term boyfriend Jack Brooksbank, it has been announced, as her mother described how the couple "float with laughter and love" in a series of gushing social media posts.
Buckingham Palace announced on Monday morning that the Queen's granddaughter became engaged to Mr Brooksbank in Nicaragua earlier this month.
Princess Eugenie's parents, the Duke of York and his former wife Sarah Duchess of York, were "delighted" to announce the engagement, while Mr Brooksbank's parents said they were "completely over the moon".
In a series of Twitter posts after the announcement, the Duchess of York posted a picture of the couple overlaid with the words: "A total embrace of goodness and joy... Eugenie is one of the finest people I know and so together it will be pure harmony".
The wedding will take place at St George's Chapel in Windsor Castle this autumn. It is the same venue that Prince Harry and Meghan Markle will wed on Saturday, May 19.
Princess Eugenie, 27, and 31-year-old Mr Brooksbank began dating in 2011 after they met while skiing in the Swiss resort of Verbier.
A Buckingham Palace spokesman said the Queen and Duke of Edinburgh "are very pleased and wish the couple all the best" following their engagement announcement.
Posing for pictures in Buckingham Palace on Monday, Princess Eugenie showed off her engagement ring that contains the rarest of all sapphires - and is perhaps a tribute to her mother.
In a statement, the palace said: "The Duke and Duchess of York are delighted to announce the engagement of Princess Eugenie to Mr Jack Brooksbank.
"Her Royal Highness and Mr Brooksbank became engaged in Nicaragua earlier this month.
"The wedding will take place in the Autumn of 2018 at George's Chapel in Windsor, with further details to be announced in due course."
The wedding will take place in the Autumn of 2018 at St George's Chapel in Windsor, with further details to be announced in due course. pic.twitter.com/3oL6F6hoYG— The Royal Family (@RoyalFamily) January 22, 2018
The Duke of York later said: "I'm absolutely overjoyed. I'm thrilled.
"Jack is an absolutely outstanding young man and Eugenie and he have got to know each other over a number of years, and I'm really thrilled for them."
The Duke said attention would turn to planning for the wedding and "getting it all organised", but "we can't fix a date yet, we've got to look at everyone's diaries. It's a bit more complicated than that."
He added: "But today it's their day. I'm just completely overjoyed for them and wish them every happiness."
Mr Brooksbank, the Stowe-educated socialite, is a former manager of Mahiki, the Mayfair nightspot that is a favourite among the rich and famous - including Princes William and Harry.
His parents, Nicola and George Brooksbank, spoke of their joy about the couple announcing their plans to wed.
They said in a brief statement: "We could not be more delighted with the news of the engagement.
"We are completely over the moon and are very excited for them both."
Prime Minister Theresa May acknowledged the news from Buckingham Palace, saying: "My very best wishes to Princess Eugenie and Jack Brooksbank on their engagement - congratulations to the happy couple."
'They float with laughter and love': Fergie shares wisdom after daughter's wedding announcement
Sarah, Duchess of York - Princess Eugenie's mother and the Duke of York's former wife - shared a series of quotes after her daughter's engagement was announced.
The Duchess - formerly Sarah Ferguson and who is commonly referred to as Fergie - posted three pictures on Twitter using the hashtags #engagement and #eugieandjack.
In three tweets, which were retweeted by the Duke of York, she expressed her happiness at the news, describing how the couple "float with laughter and love".
In the first, she wrote: "Total joy!! #engagement @TheDukeOfYork" and included a picture of the couple overlaid with the words: "A total embrace of goodness and joy. We love Jack and I am so excited to have a son, a brother and a best friend. Eugenie is one of the finest people I know and so together it will be pure harmony."
In another, which had another picture of the couple on a boat, she wrote: "They float with laughter and love .. although a boat helps! #engagement #eugieandjack @TheDukeOfYork @yorkiebea".
And in a third: "I always say that the river flows well to it's destiny because of the guidance of a solid rock #engagement #eugieandjack @TheDukeOfYork @TheDukeOfYork".
Analysis of Princess Eugenie's dress
As with any member of the Royal family posing for a portrait to commemorate an important moment, Princess Eugenie gave her engagement picture look meticulous consideration; the pink blooms pick out the rose tones of the Padparadscha sapphire in her ring while the red florals echo the walls of the Picture Gallery in Buckingham Palace and Brookbank's scarlett tie, reports Bethan Holt.
But instead of scouting out a new outfit to bring all these elements together, Eugenie shopped from her own wardrobe wearing an £1,288 Erdem cocktail dress which she was first photographed in for a shoot which appeared in the September 2016 issue of Harper's Bazaar US. Since then, she has also worn the 'Hetty' mini dress for a UN AIDS gala at Design Miami.
In the interview which accompanied the Harper's Bazaar shoot, Eugenie also confessed to doing her make-up in the car and shopping at Waitrose, making her about as "real" as Princesses come - now she can add dress recycling to that list.
Her decision to wear a dress already in her wardrobe is a contrast to the Duchess of Cambridge - who carefully matched her Issa wrap dress to the sapphire in her engagement ring - and Meghan Markle, who nodded to her pre-royal life by wearing a Line the Label coat when she and Prince Harry announced their engagement last November.
The lowdown on Princess Eugenie and her fiance
With another royal wedding in the diary, who are Princess Eugenie and Jack Brooksbank?
Who is Princess Eugenie?
Princess Eugenie Victoria Helena of York was born on March 23 1990 at The Portland Hospital in London.
She is the youngest daughter of the Duke of York and Sarah, Duchess of York, formerly Sarah Ferguson.
The 27-year-old is one of the Queen's granddaughters.
Where does she come in line to the throne?
Eugenie is eighth in line to the throne, but will be ninth in line after the arrival of the Duke and Duchess of Cambridge's third child.
What is her job?
She graduated from Newcastle University after studying English and history of art, and is now is a director at the contemporary art gallery Hauser and Wirth in London.
What about charity work?
She is patron of the Elephant Family, the Teenage Cancer Trust and the Coronet Theatre, and The European School of Osteopathy.
In 2016, she called on the public to support a social media campaign targeting modern slavery after she privately visited a London safe house for slave victims, run by the Salvation Army.
What other fundraising does she do?
When she was 12, Eugenie underwent back surgery to correct a scoliosis condition. She is now patron of the Royal National Orthopaedic Hospital.
What else do we know about the Princess?
She has posed for fashion magazine Harper's Bazaar, and shared the secrets of a day in her life, revealing she shops at Waitrose, does her make-up in the car, finds heels tricky to walk in and likes to watch Netflix.
She listed chips, Diet Coke and cashew nuts as her indulgences, and vodka soda with lime as her favourite tipple.
And her parents?
Eugenie is close to both her parents, who divorced when she was a child but remained friends. She calls her mother Sarah, Duchess of York "Mumsy".
And her fiance Jack Brooksbank?
Eugenie has been dating 29-year-old party fixer Mr Brooksbank for around seven years.
The Stowe-educated socialite was the manager of Mayfair hotspot Mahiki - a favourite haunt of Prince Harry and Eugenie's sister Princess Beatrice.
He is now the UK brand ambassador of Casamigos Tequila, which was co-founded by actor George Clooney.
What else do we know about him?
According to Tatler magazine, he is an excellent skier and the pair met through mutual friends while on a ski-trip to Verbier.
He has also said his dream is to start a chain of pubs.
Has he met the Queen?
The couple are said to have gone to meet the Queen at Balmoral for Prince Harry's 32nd birthday where the monarch reportedly gave her blessing for their marriage.
Will he be given a title?
Perhaps. Mr Brooksbank might be offered a title by the Queen ahead of his marriage, possibly an Earldom.
St George's Chapel, Royal wedding venue since 1863
St George's Chapel, at Windsor Castle, has capacity for 800 guests and has been a venue for Royal weddings since the future King Edward VII married Princess Alexandra of Denmark in 1863.
More recently, Prince Harry's uncle Prince Edward, Earl of Wessex, married Sophie Rhys-Jones - now the Countess of Wessex - there in 1999.
Peter Phillips, son of Princess Anne and Captain Mark Phillips, married Autumn Kelly in the chapel in 2008.
The Prince of Wales also celebrated his marriage to the Duchess of Cornwall there in 2005 with a service of dedication and prayer led by then-Archbishop of Canterbury Rowan Williams.
Tucked away in Windsor Castle, it is more low-key venue than central London alternatives Westminster Abbey, where the Duke and Duchess of Cambridge got married, or St Paul's Cathedral, the choice of Harry's parents Prince Charles and Diana.
While its original building dates back to the 13th century, the chapel as seen today began with King Edward IV in 1483