In London, circa 1664, she was a teenage orange-seller at the Theatre in Bridges St, but within a year "pretty, witty Nell" was one of the first actresses on the English stage noted for her comic timing and quick turn of phrase.
What really earned her notoriety was when, aged just 17, she became Charles' favourite mistress, later bearing him two sons.
But though she might have gone down in history as his preferred mistress - with a name and reputation all of London knew - was she, in fact, one of the first feminists?
Claire Chitham, who leads the cast in Auckland Theatre Company's Nell Gwynn, thinks so. On a Wednesday afternoon, in a rehearsal room appropriately located at Ellerslie Racecourse - horse racing is, of course, the sport of kings - Chitham makes her case.
"I think the thing that really set her apart from not only all the other mistresses of the time [Charles II had at least nine, and a wife] but other women of the time was that she was just brave enough or wily enough to go after what she wanted," says Chitham, best known for her roles on Shortland Street and Outrageous Fortune.
"She didn't care about asking for a title but, at some point, she started fighting for a title for her children and then to say, because the King would just put his mistresses up in apartments or parts of the palaces, 'okay, I've got this apartment but I want to own it and I want to own it freehold' and that was completely ground-breaking."
Tim Balme - playing Charles II after a seven-year absence from the stage - contributes an astute observation.
"But the interesting thing about this is that the actual feminist in the story is Charles II because he's the one who put women on the stage and if he hadn't done that, Nell never would have got up on stage.
"I'd be playing Nell Gwynn today," says Balme.
"It's a theatrical bio-pic of Nell and the great thing is you see her on this rags to riches story but it's a bit like Forrest Gump in that you see her having these great influences in moments where something she says offhand, the king takes to heart so Nell, by being Nell in her forthright and honest womanly way, has great sway over people."
Chitham agrees but adds that Nell seized an opportunity and kept working - to the ripe old age of 21 - even after she caught the king's eye. She points out Nell's friends included Aphra Behn, one of the first Englishwomen to earn a living as a writer.
"Both of these women were a part of the movement of women who, all of a sudden, were experiencing the idea they could have a career; that there were options other than menial labour or prostitution.
"Just by being their bold, brazen selves, they became trailblazers and showed other women they could step outside accepted roles in society and be part of art - to be a poet and to be an actor and to be a performer. That's an incredibly pertinent conversation today."
Speaking to Scotland's Sunday Telegraph, playwright Jessica Swale said Nell was an important actress with a rags-to-riches story well worth telling.
She told theatre critic Neil Cooper, "I don't think there's been much about her on stage or screen that presents her as anything other than a tart with a heart."
So maybe the play is an historical corrective, but don't mistake it for dour and serious. After all, it won the 2016 Olivier Award for best new comedy and Nell was a comedienne.
One of the most famous stories involves her being driven through the streets of Oxford when a mob mistook her for one of Charles' other mistresses, Catholic Frenchwoman Louise de Kerouaille, and surrounded her coach, jeering.
Nell allegedly leaned out the window and proclaimed, "Good people, you are mistaken; I am the Protestant whore."
Chitham says, "She seems to have been an everywoman who could be in a brothel and joke her way out of a terrible situation with two drunk old men then she could be at Court and still hold her own."
"She had that capability to put people at ease and be charming but not change who she was because of her circumstances."
Lowdown
What: Nell Gwynn
Where and when: ASB Waterfront Theatre, August 15-30
