Despite having only been an item for around 16 months, Meghan Markle and Prince Harry have been serious about their relationship for a while. Now the royal has popped the question to his American actress girlfriend.

So (after weeks of anticipation from the rest of us) it's official: There's going to be another royal wedding!

The proposal comes after bookies suspended odds on the announcement, with many speculating that Harry, 33, has already slipped a sparkler on the Suits actress' finger and reports that Meghan, 36, had already moved her belongings and beloved pet beagles to Britain so she can be closer to her boyfriend.

If you've been following the royal romance, you'll probably have already seen the signs that the pair are totally smitten (and we're not just talking about those adorable Invictus Games photos either). Here are just a few telling things we picked up on...

1. The fact she moved in after six months

When Meghan first met Prince Harry in May - while he was launching the 2016 Invictus Games in Toronto - a romance quickly blossomed. According to Us Weekly, "They had gotten on when they first met but it was just as friends," but then "developed romantic interests in each other and, before you knew it, they were texting every day".

The pair finally went on a low-key date to Soho House in early July. By February, they were spotted holding hands on a date night in London, amid claims she has "virtually moved in" with the prince at his two-bedroom bachelor pad Nottingham Cottage at Kensington Palace.

"Moving in with someone after seven months is relatively rare," says relationship expert Yvonne Filler, "but especially so for a royal. Being in the public eye, Harry cannot be seen to be living with lots of girls, so this was a very significant move. They were clearly confident and sure about their relationship to make such a big step so early on."

2. The fact he introduced her to the Queen

The biggest tip off that Harry was shopping for a ring on the down low came in October, when he introduced his girlfriend to his grandmother, the Queen. While this might not sound like a big deal, it was HRH that Harry needed permission from to marry Meghan (think of it like asking a dad for their daughter's hand in marriage). The three met over afternoon tea at Buckingham Palace.

"The meeting with the Queen was only two to three weeks after the Invictus Games where Harry and Meghan were very public about their relationship," says Yvonne. "They were almost certainly comfortable with the the show of affection in Toronto knowing the date was in the diary with the Queen."

3. The fact she's gushed about him to the press

While they've attempted to keep their relationship fairly private, Meghan clearly can't help letting a few details about their relationship slip. The engagement looked set in November when Meghan graced the cover of US magazine Vanity Fair and spoke openly about Harry for the first time, revealing: "We're two people who are really happy and in love."

Yvonne says: "It is rare for a statement such as, 'we're happy and in love' to be recorded about a royal relationship. She will obviously have had the permission to say how she felt, which is another indicator that the royal family are comfortable that Harry will be with Meghan long term."

4. The fact Meghan flew back to London to spend New Year with Harry

Last December, Meghan made sure she could board a flight to London to spend New Year's Eve with Harry after Christmas with her family. The pair also took a romantic break to Norway to see the Northern Lights shortly after.

"New Year at their age can be a significant night in the social calendar. The fact she made the effort to fly back to be with him was significant," says Yvonne.

"It was reported in 2013 that Cressida Bonas, Harry's girlfriend of the time, preferred a trip to Necker Island than New Year with Harry."

5. Their unmissable body language

Body language expert Darren Stanton says an image of Harry and Meghan smiling at each other as they watched Wheelchair Tennis at the Invictus Games revealed the depth of their relationship.

"This is a very telling picture that notes there is a very deep rapport and connection and an attraction right off the bat," he explains. "In psychology, there is a naturally-occurring behaviour known as matching and mirroring, which can be seen anywhere where people are getting on well.

"This picture shows extreme matching and mirroring in respect of posture, facing each other, and even though they are both wearing sunglasses, they are displaying genuine smiles."

6. The fact she shut down her blog

In April, Meghan announced that she was shutting her lifestyle blog The Tig, three years after she launched the "passion project".

"After close to three beautiful years on this adventure with you, it's time to say goodbye to The Tig," she posted. Although fans were undoubtedly disappointed to hear the news, many commentators saw the closure as a sign that Prince Harry was about to propose.

"All of these events are much stronger signals than any previous girlfriends," Yvonne adds. "She has been comfortable and relaxed from the start with the world's media and clearly understands royal protocol and what that means for them as a couple.

"He is clearly smitten and is keen to move things forward fast but in a way that both suits them and stays in line with royal expectations and title."

Time to pop the Champagne...