Prince Harry is "over the moon" to be marrying Meghan Markle.

The 33-year-old prince and the 'Suits' actress' engagement was announced on Monday morning, and Harry is "thrilled" she accepted his proposal.

And Meghan, 36, gushed she was "so happy" as she showed off her stunning three-stone diamond ring and held onto her new fiance's arm.

The 33-year-old royal - who previously dates the likes of Chelsy Davy and Cressida Bonas and was romantically linked to singers Mollie King and Ellie Goulding, actress Jenna Coleman and presenter Caroline Flack - admitted he knew Meghan was the one as soon as they met 16 months ago.

Speaking to reporters at a photocall in the grounds of London's Kensington Palace, Harry was asked when he knew Meghan was the one, and said: "From the very first time we met."

But Harry refused to say how he popped the question.

He replied: "That will come later."

But asked if it was romantic, he said: "Of course it was."

The couple posed for pictures just a few hours after their engagement was formally announced by Harry's father, Prince Charles.

An official statement read: "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.

"Prince Harry has informed The Queen and other close members of The Royal 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."

Meghan's parents, Thomas Markle and Doria Ragland, have wished the couple - who have been dating for around 16 months - a "lifetime of happiness" together.

They said in a statement: "We are incredibly happy for Meghan and Harry. Our daughter has always been a kind and loving person. To see her union with Harry, who shares the same qualities, is a source of great joy for us as parents.

"We wish them a lifetime of happiness and are very excited for their future together."