She's the woman who has stuck by Meghan's side over the years, from her time as an actress, to her early courtship with Prince Harry and now her new life after stepping back as a senior member of the royal family.
Jessica Mulroney is just one of the high profile women on Meghan Markle's long list of celebrity friends, who she considers a close pal.
The Duchess is so trusting of Jess that she even let her babysit baby Archie earlier this year in Canada, while she and Prince Harry carried out their final official duties as senior working royals.
And Jessica has leaped to Meghan's defence many times, publicly defending her against many fierce attacks.
But now as Jessica finds herself at the centre of a racially-charged scandal, it's unclear how her friendship with Meghan will be affected.
It's clear Jessica Mulroney plays a huge part in Meghan's life, so keep on reading to find out exactly how close the two women are.
How are Meghan Markle and Jessica Mulroney friends?
Jessica Mulroney, believed to be aged around 40 years old, is a well-connected Canadian stylist, consultant and wedding planner.
Meghan and Jessica are thought to have met when Meghan first moved from LA to Toronto, in 2011, to film Suits. Meghan and Jessica bonded over their love of yoga and travel and have enjoyed several European jaunts together.
Jessica was pictured with Meghan, Prince Harry and Meghan's mother Doria Ragland at the Invictus Games Closing Ceremony in Toronto in 2018.
Now their friendship is facing its greatest ever test - Jessica's racism scandal
Jessica became embroiled in a racial scandal with black Canadian influencer Sasha Exeter.
In June, Sasha posted a generic message on Instagram, calling on other high profile influencers to use their platforms to show support for the Black Lives Matter movement.
While Sasha's post didn't name Jessica specifically, Jess took the message as a personal slight. She then sent a series of private texts and emails to Sasha, which ultimately resulted in Jess reportedly threatening to sue her.
Sasha outed Jessica in an extended Instagram video, later leading to several apologies from Jess. She even referenced Meghan in her apology, explaining she had some understanding of racism due to Meghan's own experiences.
"I have lived a very public and personal experience with my closest friend where race was front and centre. It was deeply educational,"Jessica wrote in the comments.
However, the controversy led to Jessica losing her coveted role as a Good Morning America contributor, her show I Do, Redo was axed and she took an extended break from social media.
Meghan is yet to publicly comment on the controversy, though a royal source told the Daily Mail she was reportedly "mortified" by the ordeal.
Jessica played a starring role in Meghan's royal wedding
We all remember that moment when Duchess Catherine's sister, Pippa Middleton, unintentionally upstaged the bride on her wedding day to Prince William in 2011, when she walked down the aisle in a figure-hugging dress that perfectly accentuated her incredible physique.
So it was like history was repeating itself when Meghan Markle married Prince Harry, with many eyes wandering to the woman in blue, Meghan's best pal Jessica.
Jessica, who acted as Meghan's "unofficial" maid of honour at her wedding to Prince Harry in May 2018, had a "Pippa moment" herself when her enviously pert backside and toned arms caught the attention of the millions watching around the world, as she made her way into the church with the adorable bridesmaids and page boys.
Jessica is such a dear friend of Meghan's that her three children, daughter Ivy and twin boys Brian and John, were asked to be included in the wedding as bridesmaid and page boys.
In fact, it was one of Jessica's seven-year-old twin sons, Brian, who's awestruck expression went viral during the televised wedding, capturing the internet's heart.
As Meghan was making her way down the aisle of St George's Chapel in her stunning Givenchy wedding dress, Brian's beaming, joyful face was visible behind the bride as he wordlessly communicated what everyone was feeling in that heart-stopping moment.
After the wedding, Jessica took to Instagram to post about the "magical weekend" she had celebrating her friend.
Sharing a picture of her boys trailing Meghan carrying her dress to Instagram, the Toronto-based mum wrote: "Proud friend. Proud mum."
Who's Jessica Mulroney's husband?
The mother-of-three and her presenter husband Ben Mulroney, who is the son of former Canadian Prime Minister Brian Mulroney, were believed to be some of the first people Meghan introduced Harry to.
Jessica and Ben Mulroney are considered one of Canada's most glamorous power couples and according to a recent report in Vanity Fair, it's believed their social ties helped connect Meghan to Harry.
The pair consider Canadian PM Justin and his wife Sophie Trudeau as close friends.
"The Jessica Mulroney relationship was key in that it opened up the eco-system of her world. It's what probably connected her to people like Justin [Trudeau] and to Sophie, and I think also to Markus [Anderson] and Soho House," Toronto-based reporter Shinan Govani told Vanity Fair.
WATCH: Jessica Mulroney helps Meghan Markle with her wedding dress: