The second daughter of Prince Andrew, Princess Eugenie is to marry her long-term boyfriend Jack Brooksbank in Windsor Castle in the autumn.
The Duke and Duchess of York said their younger daughter and Mr Brooksbank became engaged while in Nicaragua earlier this month.
In a series of tweets, Sarah Ferguson congratulated her daughter and her fiancé. She said the couple ‘float with laughter and love’.
‘We love Jack and I am so excited to have a son, a brother and a best friend,’ the duchess added.
The wedding will take place at St George’s Chapel, Windsor Castle, in the autumn, after Prince Harry and Meghan Markle also tie the knot here in May.
The princess and her fiancé have dated for many years after meeting on a ski holiday.
A Buckingham Palace spokesman said Princess Eugenie’s grandparents, the Queen and the Duke of Edinburgh, were ‘very pleased and wish the couple all the best’.
Mr Brooksbank’s parents, Nicola and George Brooksbank, said they were ‘completely over the moon’ and ‘very excited’ for the couple. ‘We could not be more delighted with the news of the engagement,’ they commented.
In the official engagement photographs Princess Eugenie is wearing a dress by Erdem, shoes by Jimmy Choo and her engagement ring contains a padparadscha sapphire surrounded by diamonds.
The 27-year-old is the second daughter of Prince Andrew and Sarah, Duchess of York, and is eighth in line to the throne after her sister Princess Beatrice.
Princess Eugenie will keep her royal title when she marries Mr Brooksbank and will have the option to take his surname.
The princess works in the arts as a director at gallery Hauser and Wirth, she does not carry out any royal engagements, and she is patron of several organisations including the Teenage Cancer Trust.