The anonymous internet diary was fearlessly candid. Penned in a confessional style, its author — an aspiring young Hollywood actress with a salty turn of phrase and a keen eye for detail — chronicled her triumphs and tribulations as she "hustled" in search of stardom.
Some entries exposed the darker side of Tinseltown. The tyrannical casting directors and "bitchy" rivals with whom she vied for roles, for example, and the hard-driving producers who treated the cast like "show ponies", enlisting a doctor to inject them with vitamins so they stayed fit for work.
She laid bare her "roller-coaster" emotions, which swung back and forth with success and failure, reports Daily Mail.
When she passed an audition, her confidence soared and the champagne corks popped; when she was rejected, she would spend the day "sobbing in bed with a bottle of wine and a box of biscuits".
Then there were the daily indignities and the financial hardship she endured as she clawed for recognition.
"I've had to freeze my [acting] union membership, borrow money, work jobs that I hated, endure being treated like s**t on a set, kiss actors with smelly breath and cry for hours on end because I just didn't think I could take it any more," she wrote.
The young actress also described, in less than delicate terms, how awkward it felt to act out a love scene with an actor whose passions had run away with him.
Quite clearly, she couldn't risk putting her name to such a nakedly candid blog, which first appeared in January 2010 and became a "must read" for budding actors, according to one entertainment industry website. To do so would have been tantamount to committing professional suicide.
For as the long-hidden predations of Harvey Weinstein, Kevin Spacey and others have since demonstrated, the Hollywood establishment guards its secrets closely and would not have taken kindly to an upstart performer turning the spotlight on the industry itself.
So she simply called herself "The Working Actress" and used a silhouette of an empty director's chair as her logo, declining to identify herself even when mainstream news channels began clamouring to interview her.
She remained incognito and wrote her final piquant post, in the summer of 2012, whereupon she signed off from the internet without a word of explanation or farewell.
By then, she had described the thrill of landing her big break, a starring role in a new TV series, and her abrupt departure inevitably caused her disappointed readers to speculate about her identity.
But the guessing game started again after it came to light that the diary had been removed from the internet.
Today, however, I can unmask "The Working Actress".
Given the position that she is about to assume, we can well understand the possible motive for this cloak-and-dagger image-polishing operation.
So step forward, out of the shadows, Meghan Markle.
The revelation that Prince Harry's fiancee was the diary's author comes from impeccable sources in California.
"It was a way for her to vent her frustrations and try to have a voice in the industry. I think it was also a way to inspire other struggling actors — and herself, too — to keep going," one said.
By recovering some of the entries and matching them with events that occurred in Meghan's life, and also with remarks she later made in interviews, I have uncovered more evidence to conclusively prove that she is the mystery Hollywood whistleblower.
In truth, the task wasn't all that difficult, for Meghan became rather reckless towards the end of her time as a secret diarist, leaving many clues as to her identity.
Speculation that Meghan was the blogger began circulating on internet forums in November after her engagement to Harry was announced.
"It's weird that this blog disappeared. There isn't a trace of it on the net any more. I remember people thinking that Meghan Markle wrote it. And seeing how the blog had disappeared, I wouldn't be surprised if that's true,' a woman called Stephanie posted.
"Yeah, it was definitely Meghan who wrote it," responded Lance Carter, a Hollywood actor who has appeared in films and TV shows.
"I think she deleted it a while ago. Maybe when she [joined the TV legal drama] Suits?"
However, being named ought not to cause her embarrassment, for the advice and inspiration she gave in her columns was invaluable to acting newcomers, some of whom posted comments thanking her for helping their careers.
Her observations — by turns poignant, insightful and ribald — were also enormously entertaining.
Furthermore, since Meghan described her experiences and thoughts in the form of a personal diary — "as if no one was reading", as she put it — it is what historians would call a "primary source": an intimate first-hand account of the extraordinary ascent that began in the showbiz backwaters.
As we now know, after she became well-known for her role in the TV series Suits, Meghan launched a second blog which she called The Tig (after her favourite Italian wine, Tignanello).
By then, however, she had an image to cultivate, so The Tig took on the mantle of an uber-cool lifestyle magazine, featuring Hello!-style interviews with people in her elevated new social circle, plus reviews, fashion and beauty tips, and essays on lofty humanitarian issues.
It showed the sassy but sophisticated woman Meghan had become, and whom Prince Harry will marry in May.
This secret diary was penned without self-censorship, during her late 20s and early 30s — a critical period in her life that saw her metamorphose, butterfly-like, from near-obscurity to well-known network TV star. It is Meghan in the raw, so to speak.
Her posts, particularly the early ones, reveal how greatly she was influenced by her first husband, Hollywood producer Trevor Engelson, whom she married in 2011, having previously lived with him for six years.
Meghan used similarly tough language, punctuated by expletives, and borrowed some of his trademark sayings.
"Don't give it five minutes if you're not going to give it five years," she advised would-be actors — a motto voiced by Engelson in an interview. Announcing her new blog on Facebook, in January 2010, she declared: "I am a working actress. And I don't have an entourage. Not a star. Not in the tabloids"
"The kind of girl who is sometimes recognisable-ish. The operative word being 'ish'.
"I don't wait tables. I don't have a side job. I am in the club of the fortunate few that sometimes make a living playing dress-up.
"When it's good, it's f****** awesome. The other 300-plus days, it's harder than most would think. Humbling. Gruelling. Sometimes mind-numbing.
"But at the end of the day it's all worth it. People often describe actors who pop onto the scene as 'overnight success stories'. 'Here's the reality — it's more like years of hustle . . . welcome to the hustle."
Behind her hard facade, however, Meghan — who described her diary as "a cathartic way to document my experiences" — often felt angst-ridden and deeply insecure, particularly between jobs, when she wondered where the next pay-cheque was coming from.
"I was swimming in negative thoughts during the day and needed to tell myself (trick myself, even) that I would work," she wrote in March 2010, revealing how she had taught herself a new mantra to block out her gremlins.
When she attended one audition, she found herself being ticked off "like a f****** three-year-old" for failing to bring a headshot photograph and CV with her, as is customary.
"I find myself in this moment losing every ounce of patience. Not just because [the casting agent] is being ridiculously condescending . . . but because she gets away with talking to an actress that way. It blows my mind.
"Perhaps she assumes I'm a non-union actress and this is my 4th audition ever . . . it drives me crazy."
After such days, or when her minor scenes were cut from a film — often after "months of work and anticipation" — "The Working Actress" admitted that she would be plunged into despair.
"It's those kind of discoveries that are humbling as they are mind-numbing, and have sent me into a tailspin of sobbing in bed with a bottle of wine and a box of cookies. But it's part of the game."
And in a separate anonymous interview to promote the blog, she said: "Rejection, I find, is hardest when you want the part sooo badly. It can never become your be-all and end-all, but sometimes it feels that way.
"I'm not gonna lie, I've spent many days curled up in bed with a loaf of bread and some wine. A one-woman pity party. It's awful and ridiculous."
Last November, Darling magazine marked her engagement to Prince Harry by republishing an article Meghan had written for them, in which she also described the depths she sunk to during low points in her career.
In her early 20s, she drove around in "a beat-up Ford Explorer Sport that rattled like a steamboat engine", and had to crawl in through the boot because the front doors had jammed.
When attending auditions, she parked the jalopy at the back of the car park so no one would see it, she recalled.
Then, after failing to get a part, she wrote, she would spend the evening 'eating my feelings with grilled cheese sandwiches and cheap wine'.
Her self-esteem improved after the influential casting director April Webster took her aside and said simply: "You need to know that you're enough." The remark left Meghan "breathless".
However, Meghan would bring levity to her diary by reporting mischievously and amusingly about her experiences on set.
In November 2010, when a website asked her to discuss the pitfalls of acting a love scene, she said she had sometimes had to call a break, take the producer aside and "share how incredibly awkward it is when the guy playing your boyfriend is grinding a little too hard into you". She continued: "But as a guest star, I feel you have to kind of suck it up. They toss in a kissing scene for no apparent reason, they change your outfit from jeans to a dress the size of a loincloth . . . sometimes it's just part of the job."
Other posts reveal Meghan, pre-stardom, to have been endearingly naïve. When she got a 30-second walk-on part as a FedEx delivery girl in the Jennifer Aniston comedy Horrible Bosses, she found herself on the same set as one of her acting heroes, Donald Sutherland.
"I was so excited to work with him," she enthused. "The woman in the hair department said he was a gem and that I would love him, so when I met him (and his oh-so-debonair self), I said: 'Mr Sutherland, I hear I'm going to fall in love with you before lunch-break.' He laughed, it broke the ice. And I resisted the very major urge to squeal."
When she recounted this story, she didn't reveal her part, or name the film — which was shot in 2010 and came out the following year — for fear of betraying her identity. But the fact that she briefly appeared in the comedy with Sutherland is yet more proof that she was the secret diarist.
By then, Meghan, alias "The Working Actress", had finally got the breakthrough she dreamed of and couldn't resist sharing her delight with her followers, though, of course, she didn't disclose the name of the new drama in which she had landed a starring role.
Rather bravely, we might think, she continued with her racy confessions. "Come and read about the girl with the magical boobs!" she teased readers in a tweet in February 2011.
Another Twitter plug for her diary, two months later, was equally cheeky: "Come and read about sex. Lots of sex! (I swear my Twitter account wasn't hacked)."
As the diary pages to which these tweets referred can no longer be viewed, whatever tantalising revelations she made have now vanished into the ether.
However, some of her later posts are retrievable, and appear to show how stardom changed her personality. They support the assertion of her long-time friend, Ninaki Priddy, who told the Mail last year that she had known two very different Meghans: "Meghan before fame, and Meghan after fame".
In early posts, the actress had bemoaned missing her 'loved ones' when she was away on location.
"It's incredibly tough . . . that part kills," she said, adding somewhat contradictorily: "But it's also like a mini vacation (if you have any days off) — to be a tourist with a per diem!! [day-rate fee] . . . amazing."
Presumably, these "loved ones" included her then husband. Yet it seems that when Meghan's career became more glamorous, it took a toll on her marriage.
For in August 2013, the couple divorced, with Meghan — by then living in Toronto to film Suits — citing the big geographical distance between them as the reason for the break-up.
Interviewed, again anonymously, by a Hollywood podcast (in which she dropped more clues to her identity, mentioning that she had acted in high school and attended an out-of-state university), "The Working Actress" insisted she was not interested in stardom for its own sake.
"I never wanted to be famous," she said. "I have always wanted to make a living by playing dress-up and working with awesome people.
"I loathe walking the red carpet. It makes me nervous and itchy, and I don't know which way to look. I just revert to this nerdy child that I once was. I hate it. I get off the carpet and have to shake it off. Sounds dramatic, but it's really nerve-racking for me."
This was her speaking in March 2010, before her Suits breakthrough brought her first flirtation with true celebrity.
Two years later, when she attended a glitzy New York event called Upfronts, at which major U.S. TV networks unveil programmes for the forthcoming season for prospective advertisers, her opinions on celebrity seemed very different.
Meghan appears to have accepted the price of her newfound fame — and to be rather enjoying it. She wrote: "I am part of the horse and pony show this year. The scruffle (sic) has already begun with production and PR — the outfit I will wear, the hotel I will stay at, the parties I will attend . . . the first-class flights the studio sends me out on.
"They roll out the red carpet in a major way because they want me ('the talent' as they call us . . . ) to show up looking and presenting in the best possible manner.
"This is the ultimate 'dance monkey, dance'. Now let me say this — as much as some people might hear this description and feel nauseated by it (that inner monologue of 'but I am an artiste') I say this to you, dear friend: Get over yourself.
"This is part of the job, and it's f****** awesome. It's fancy and it's cool, and it's the business of what it takes to make it in this business.
"If you are pursuing television, then realise that you have already sold out, and take your big fancy paycheck to produce your 'artiste' - driven plays on hiatus [in between TV roles]. Because you can now.
"Because flashing those pearly whites (ahem, veneers) and working the red carpet with your sexy little body (ahem, Spanx) is part of the job description you jumped on board for when you were lucky enough to sign on the dotted line that day you were testing [auditioning].
"This is what we call a high-class problem. And compared with the problems of what feels like many moons ago (not having money to fill up my gas tank, Scotch-taping my headshots and CVs [to audition applications] because I ran out of staples, crying because I couldn't get a call back, or even an audition — when I knew in my core that I was the best possible one for the part), I will take this any day."
Other incognito blogs, written after Suits had become a successful show, suggested she was acquiring airs and graces.
She sounded a tad condescending when she wrote about being recognised by the handyman who had come to mend her dishwasher, and — horror of horrors — asked her to pose with him for a selfie 'to prove to his brother and dad that he'd met me'.
Then there was 'Jim', a hapless chauffeur assigned to collect her from an airport. His first faux pas was to brandish a sign revealing her full name ('kind of a no-no, usually it's just a first initial and last name').
His second was to show her personal photographs on his iPhone as they waited for her luggage, thinking she might be the least bit interested. To cap it all, the inept driver had dropped her off at the wrong address.
Of course, Meghan might have been telling these prima donna-like stories with tongue firmly in cheek, to entertain her readers.
Certainly, she seemed more reflective in a later post, writing plaintively: 'I have to be honest — I had no idea what being a working actress would entail.
"I work long hours, I travel for Press, my mind memorises. My mind spins. My days blur. My nights are restless. My hair is primped, my face is painted, my name is recognised, my star meter is rising, my life is changing."
Last night, a Kensington Palace spokeswoman for Miss Markle said there would be no comment. However, according to a well-placed source who knew Meghan, she put a great deal of thought into the blog, and it was very much a reflection of her character.
"The 'Working Actress' persona was like a therapy for her," says the insider. "It allowed her to lay bare her struggles and also call out to some industry people while remaining anonymous. She really wrote it in her own voice.
"But once her career took off and her lifestyle blog (The Tig) started doing well, she stopped writing this one. That was the platform she truly wanted.
"She no longer wanted to be known as the 'struggling actress'."
The source added: "I think this shows a side of Meghan people might not expect. It is not the image she likes to portray.
"She stopped writing long ago, but I'm not sure when the pages were deleted. Maybe she was worried about being outed. It definitely doesn't fit the image of a royal."
Indeed it does not. But then, as her fascinating secret diary shows, Meghan is a free-spirited woman, and she promises to be a highly unconventional duchess.