Although Ms Markle and Prince Harry have been dating for almost 18 months, the first real indication that things were heading towards the Westminster Abbey doors was the recent 'official' public outing of the couple at the Invictus Games - the snaps showed a seriously loved up couple having a ball together.

And now we know why. That official outing was the warm up to the main event: a royal engagement.  Overnight Clarence House announced Prince Harry is to marry US actress Meghan Markle in the northern hemisphere spring of 2018.

Fun-loving red-haired Prince Harry is currently fifth in line to the throne after his dad Prince Charles, brother Prince William, nephew Prince George and niece Princess Charlotte, however his sister-in-law the Duchess of Cambridge aka Princess Kate is pregnant with bub number three, so when he or she arrives in April 2018 - the Prince will be bumped to number six.

No worries for Markle she'll still score a stellar title, which according to ET, is rumoured to be 'Her Royal Highness, the Duchess of Sussex' (the Queen will confer Markle's title on the morning of their wedding - so we'll have to wait until then for final confirmation).

As for the important details like the ring, according to the BBC, "Kensington Palace said Ms Markle's engagement ring was designed by Prince Harry and features two diamonds which belonged to his late mother, Diana, Princess of Wales." The third centre diamond is reportedly from Botswana where Prince Harry and Markle travelled to together earlier this year to celebrate the actress's 36th birthday.

Meghan Markle engagement ring (image: Getty)

Markle just wrapped filming on the seventh season of hit TV show Suits, her last season on the show and recently moved to London to be close to her royal beau. No news yet on whether she'll be giving up her acting career for good once she marries her prince.

But with the engagement marking a more modern mood for the monarchy - Markle is a divorced American actress which would have been frowned upon if not reason for a royal abdication in the past (remember King Edward VIII's forced abdication back in 1936 after marrying American divorcée Wallis Simpson?) - surely she'll still be able to tread the boards after becoming a princess if she desires.

According to the BBC interview Prince Harry and Markle gave shortly after the announcement, Prince Harry proposed, "...earlier this month at the couple's Nottingham Cottage at Kensington Palace" while the couple were "roasting a chicken."

In the interview Markle says the proposal was, "... so sweet and natural and very romantic. He got down on one knee. As a matter of fact, I could barely let you finish proposing. I said, 'Can I say yes now?'"

Who'll design the dress is anyone's guess at this stage but if the chic white coat Markle wore for the engagement announcement from Canadian brand Line the Label  is any indication, a Canadian or US designer could be next in line to design a royal wedding dress.

Watch the heart-warming BBC interview below:

 

A royal engagement! Prince Harry puts a ring on it