She's gone from a humble Scouser who grew up in a council house to the Queen's most trusted member of staff.
And although Angela Kelly's upbringing couldn't be more different to the monarch's, the pair have struck up a close and cosy bond over the last 28 years.
It seems the two women know each other inside out with the Queen even once reportedly remarking "we could be sisters".
Such is her fondness of Angela, Her Majesty gave her "extraordinary permission" to release the book - The Other Side of the Coin - which featured never before seen behind-the-scenes photos and insider information about life at Buckingham Palace.
And earlier this week, it was announced that an updated version of the book is to be released next month to coincide with Her Majesty's Platinum Jubilee celebrations.
So how did the Queen and a crane driver's daughter strike up such a close friendship? Here we take a look...
Humble beginnings
Angela is the daughter of a crane driver and nurse, who grew up in a council house in Walton, Liverpool.
When money was tight, Ms Kelly rummaged through fabrics in the city’s flea markets to make clothes. As a young woman, she adored The Beatles and was always immaculately turned out.
The mum-of-three previously spent time in Germany working in the catering department of the British Army.
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It was there that she had a brief marriage with a German man before she met husband number three, Irish Guardsman Jim Kelly, in 1989.
It was in Berlin in 1992 that she had her first chance meeting with the Queen when she was working as a housekeeper for the British Ambassador to Germany.
Her Majesty visited the ambassador's home while on a visit to Germany and just a year later, on returning to the UK, she was offered a position as the Queen's dresser.
In an interview with The Telegraph in 2007, Angela said of her hiring: "I suppose the Queen must have liked me and decided I was trustworthy and discreet."
Memorable looks
After several years of working as the Queen's dresser, Angela then bagged the coveted position of being the monarch's dressmaker.
According to the Daily Mail, this came after the Queen had asked her opinion on some new designs.
Angela is behind some of Her Majesty's most resplendent and iconic outfits. They include the jacket dress she wore to Prince William and Kate's 2011 wedding.
She also regards the Queen as a "fashion icon" and they work carefully together to curate her wardrobe.
Introducing Her Majesty to the stage to present an award at London Fashion Week last year, Angela said: "Your Majesty, I know you do not wish to be known as a fashion icon, but from all of us in this room, we have the utmost respect for you and also for your hard work and diligence."
Cosy bond
But as well as having a successful working relationship, Angela and the Queen are said to be very close - with Angela being one of her few confidantes.
It has been reported that the pair love nothing more than having a natter over a cup of Darjeeling tea at Angela's grace-and-favour Windsor home.
And it is said that when the Queen tells staff she is "stepping out for a bit" it is actually royal code for her popping to see her friend
They discuss "everything and anything" from treasured grandchildren and great-grandchildren to new ranges of make-up.
"We are two typical women," Ms Kelly told The Telegraph in a rare interview in 2007.
"We discuss clothes, make-up, jewellery. We say, 'Would this piece of jewellery look nice with that outfit?', and things like that."
Angela has only given a handful of interviews but when she has spoken out publicly, she has gushed about her unwavering affection for her boss.
She has described how much she "adores" and is "so proud of her".
She also divulged the Queen's surprising hidden talent - doing all sorts of accents, including Ms Kelly's Scouse twang.
Their close relationship has however reportedly caused jealousy among other members of staff, with Angela once joking: "I don't have any more room for knives in my back."
She added: "I don't know why the Queen seems fond of me - because I don't give her an easy time!"
Grand title
Now having served the Queen for almost 30 years, Angela holds a job with a very grand title - Personal Assistant, Adviser and Curator to Her Majesty The Queen (Jewellery, Insignias and Wardrobe).
Not only that, Angela became a member of the Royal Victorian Order before being promoted to a Lieutenant of the Royal Victorian Order.
The Queen is said to have once told her: "You and I do work well together. I think we are a good team".
Extraordinary permission
In 2019, Angela became the first member of the royal staff to be given "extraordinary" permission from the monarch to release a book.
Called The Other Side of the Coin, it featured never before seen behind-the-scenes photos and insider information about life at Buckingham Palace.
According to the publisher Harper Collins, the new updated version of the book, out next month, will feature new photographs as well as a brand new chapter.
Covered in this chapter, Angela will talk about the royal household's isolation during the Covid-19 lockdown at Windsor Castle, which saw her taking on new roles such as cutting and setting the Queen's hair.
The chapter will also cover Prince Philip's funeral, the Queen's first public engagement post-lockdown and a look ahead to June's Platinum Jubilee celebrations.
