The actress' parents say they are "incredibly happy" for the couple, while The Queen and the Duke of Edinburgh are "delighted".
MEGHAN Markle showed off her sparkling engagement ring as her fiancé Prince Harry revealed he knew she was The One “the very first time we met".
The smitten royal designed Meghan's ring himself with two diamonds belonging to his late mother Diana, Princess of Wales.
The Suits star stroked Harry's arm as they walked hand in hand for their first appearance in public since the announcement of their engagement.
Standing in The Sunken Garden at Kensington Palace, the happy couple beamed in front of the world's press gathered outside.
Wearing a white coat by Canadian brand Line the Label and a dress by PAROSH, Meghan said she was "so very happy, thank you" to be engaged to Harry.
The prince said he was "thrilled, over the moon" adding: "Very glad it's not raining as well."
He said the details of his proposal would "come later", but admitted it had been very romantic.
The couple were smiling and giggling throughout their appearance.
Kensington Palace said the prince designed Meghan's engagement ring himself - using two stones which belong to his late mum, in the year of the 20th anniversary of her death.
The two outside stones are diamonds from the personal collection of Diana, Princess of Wales.
At the centre is a diamond from Botswana, a country that holds special significance for Harry who has visited many times since he was a child.
It is also a place the couple has spent time together over the last year and a half, Kensington Palace said.
American actress Meghan will live with Prince Harry in Nottingham Cottage at Kensington Palace once they are wed next year.
Announcing their engagement earlier today, a palace spokesman said: "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.