The American-based designer - who reportedly first set up the Duke and Duchess of Sussex on a blind date - is marrying energy entrepreneur Michael Hess this weekend in an elaborate ceremony in Rome.
The Duke and Duchess of Sussex are among the guests. They have reportedly flown to Rome without their son Archie.
Other attendees at the wedding are Orlando Bloom and pop star Katy Perry, who were photographed at a pre-wedding party in Rome on Thursday night along with fellow guests Karlie Kloss and Joshua Kushner.
Ivanka Trump as well as Princess Beatrice and Princess Eugenie are also on the guest list.
Who is Misha Nonoo?
Nonoo, 33, is a fashion designer known for her sustainable, sleek and timeless designs and her close friendship with the Duchess of Sussex.
She famously created The Husband Shirt, which Markle wore during her first public appearance with Prince Harry at the Toronto Invictus Games in 2017.
Nonoo recreated a version of the design for Markle's SmartWorks charity capsule collection.
The designer was born in Bahrain to an English mother and Iraqi-Jewish father and raised in London. She was previously married to Paddle8 founder Alexander Gilkes, who is close friends with Prince Harry and Prince William as they attended Eton together. They divorced in 2016.
She met Markle at a luncheon during Art Basel and they became close friends, often sharing Instagram posts of each other. “We were seated next to one another at a lunch, and we got along like a house on fire,” Nonoo told The Evening Standard.
Now, she splits her time between New York and London.
"I was drawn to the entrepreneurial spirit that exists in the US. Building a New York network, putting myself out there on a day to day basis and making a name for myself was obviously hard to start with but over time, it became easier. New Yorkers are great at encouraging like-minded people to pursue their dreams," she told Insider.
Who is Michael Hess?
Michael (or Mikey to his friends) is an American oil tycoon. His family is said to be worth $1.9 billion.
His grandfather started the Hess Corporation and also purchased the New York Jets football team and owned them for 15 years. Mikey's dad John is now heading up the family business, so it's more than likely that he's next in line. Like his father, Mikey attended Harvard College and then Harvard Business School.
— Heidi Klum (@heidiklum)
He proposed to Nonoo during a Valentine's Day trip to Cabo San Lucas. He's been friends with Joshua Kushner since their Harvard days. Fittingly, Nonoo is quite close with Kushner's wife Karlie Kloss, who appeared at Nonoo's recent pop-up shop launch. He's also said to be close with supermodel Heidi Klum.
While his Instagram is private, according to The New York Times he posts pictures of "Mick Jagger close-up in concert, courtside seats at a Knicks game and stops on his trips around the world."
His 30th birthday party in the Hamptons was quite the extravaganza - with a performance from Nelly and Taylor Swift, as well as appearances by Klum and Leslie Odom Jr., so expect a suitably star-studded guest list for his upcoming nuptials.
Who's on the guest list?
Meghan Markle and Prince Harry arrived in Rome prior to the wedding.
Katy Perry and Orlando Bloom, Karlie Kloss and Joshua Kushner, and Princess Beatrice and Princess Eugenie are also on the guest list.
Princess Eugenie was recently spotted at Nonoo's glamorous pop-up boutique opening in Manhattan during New York Fashion Week.
British comedian James Corden is also attending the wedding, as is First Daughter Ivanka Trump.