Clarence House announced the engagement, setting the wedding for Spring 2018
But now Meghan is due to join the family – who better to give her advice than the Duchess of Cambridge.
Kate Middleton has barely put a foot wrong since becoming an HRH – so she’s probably the perfect person to offer her future sister-in-law some words of wisdom on life with the Windsors.
Get to know granny
The Queen, with her many years of experience, has much to teach royal newbies.
She’s also ‘The Boss’ – what she says goes.
This could be everything from the uniform Harry must wear on his wedding day and how royal children should behave on the Buckingham Palace balcony to etiquette for official engagements.
As the Duke of Cambridge once said: ‘You don’t mess with your grandmother.’
Watch out for the long lenses
Kate was snapped sunbathing topless by photographers while enjoying a break in the south of France in 2012.
William was furious at the intrusion and a costly legal fight and court case ensued, with William and Kate being awarded more than 100,000 euros in damages.
Make sure you have a trusted circle of friends and staff
Within Kate’s close circle of confidantes, long-term friend Sophie Carter was rewarded for her loyalty by being asked to be Princess Charlotte’s godmother.
Ms Markle will need to be able to rely on friends not to blab to the media about her life with Harry.
Staff are also vital for ensuring the smooth running of royal life
William and Kate have a nanny, a housekeeper, an orderly, as well as their bodyguards.
Kate also has a private secretary, a PA and stylist, and a press team, and when she is on tour, her hairdresser goes too.
Get a house in the country
Anmer Hall, a wedding gift from the Queen, has given Kate, William and their children, sanctuary and privacy away from London.
The 10-bedroom country retreat, which is a short drive from Sandringham House in Norfolk, underwent a major refurbishment overseen by the Cambridges.
You won’t need your own jewels
The Queen often loans priceless jewellery to family members, meaning there is no need for Ms Markle to head to Cartier to begin her own collection.
Kate borrowed one from the monarch for her wedding.
Focus on your own interests
Kate has been careful to support charities which reflect her passions – such the arts, tackling bullying and improving the mental health of children.
She is likely to guide Ms Markle into doing research and taking her time before picking patronages – many of which she will be committing herself to for decades.
The kids come first
For William and Kate, protecting their children from the limelight and intrusion is paramount.
In 2015, Kensington Palace accused paparazzi photographers of harassing Prince George, saying the royal youngster had become their ‘number one target’ and accusing them of going to ‘extreme lengths’ to get pictures of him.
George and Charlotte are rarely seen in public, except on overseas tours and at the occasional UK appearance, and the Duke and Duchess release a number of photos throughout the year in an attempt to keep the public and press happy.
Their first meeting
Prince Harry was in Toronto (where Suits is filmed) in May 2016 to launch the 2017 Invictus Games
'They got on just as friends' when they first met, Us Weekly said. But they ended up messaging each other constantly. They later admitted that they'd started dating pretty quickly after meeting
A 'regular' visitor
After a couple of dates, first with friends then by themselves, Harry apparently made a trip to Meghan's apartment in Toronto
it becomes public
Newspapers begin reporting the story at the end of October 2016, saying Harry 'has a notable spring in his step and can't stop smiling'
The return journey
In a filming break in November 2016, Meghan is reported to make the return to the UK to Harry's Nottingham Cottage at Kensington Palace
8 November 2016
HArry tells the press to back off
Harry goes public, saying that 'his girlfriend, Meghan Markle, has been subject to a wave of abuse and harassment'
Things get serious
Rumours of Harry popping the question began in November 2016, with a source telling E News that 'this is totally Harry. The problem with Harry is when he falls, he falls hard. He goes in big time'
A formal introduction
After holidaying with Harry in Norway, she was formally introduced to Kate, the Duchess Of Cambridge, in Kensington Palace
The couple were spotted holding hands as they left London's Soho House
A first public outing
With Harry competing in the Audi Polo Challenge, the couple didn't pose together but Meghan cheered from the sidelines, with photographers capturing a kiss later in the event
20 May 2017
Pippa Middleton's wedding
Meghan was Harry's official +1 at the wedding of Prince William's sister-in-law Pippa
A romantic getaway
They holiday in the Meno A Kwena camp in Botswana, in the heart of the African bush
25 September 2017
An actual joint appearance
The 2017 Invictus Games is the first properly photographed public appearance they make, walking hand-in-hand into the event
22 November 2017
The big move
Meghan moves out of her Toronto home without, for the moment, her dogs, to move in with Harry in Kensington. She will leave her role in Suits, it is believed.