We have a pretty convincing theory about why Meghan and Harry got engaged so quickly.

After months of speculation, on Tuesday it was confirmed that a man and woman had got engaged.

And by ‘man and woman’ we mean Suits actress Meghan Markle and Prince Harry. (Their names may sound a bit familiar).

Since then, we’ve lapped up every single detail we can about the proposal (over roast chicken, how romantic), the ring (v thoughtful), their clear adoration for each other (excuse me while I cry into my Ben and Jerry’s) and their wedding plans (May next year.)

Yep, that's just SIX MONTHS away. The pair had been dating just over a year before getting engaged, which makes it just over 18 months between the first date and the wedding.

We have a pretty convincing theory as to the "whirlwind" timeline of the relationship.

You see, while being a 'girlfriend' to a Royal is rather exciting, there are some things that only come with being an official member (or member to be) of the royal family. The top of that list? Security.

Listen: Meghan Markle Is The Role Model Young Women Need. Post continues after audio.

Taxpayer funded security personnel is only afforded once this is the case, and judging by the frenzied interest in Markle since her relationship with Harry was confirmed, it was much needed.

Now, we are definitely romantics and it was clear from the official engagement interview that Meghan and Harry are besotted with one another. But if you're madly in love, haven't been together that long and suddenly become the new focus of every person in Britain, being able to access this kind of security is probably bloody attractive.

So it could indeed be a big reason for the pair's relatively quick engagement, particularly by Royal standards.

The Sunday Express reported the days leading up to the engagement announcement was the first time the 36-year-old had been seen with taxpayer funded security, which was taken as indication the news would be imminent.

It was a similar case with the Duchess of Cambridge, who was only given police protection AFTER she became secretly engaged to Prince William in October 2010. The official announcement was made a month later.

Another speculated reason for the short wait is due to Prince Harry's grandparents.

Royal expert Kate Nicholl told Entertainment Tonight she believes he was concerned about Prince Phillip's age.

"His 96-year-old grandfather, the Duke of Edinburgh, is retired now and Prince Harry really wants him to be at his wedding,” she said.

"He's incredibly close to his grandfather and, being 96, Harry thought it was it was a great thing to [have] the wedding sooner rather than later, so his grandfather could be there, fit and healthy.”

Either way, we can't wait.