'Bridgerton' just made its boldest book change yet — but how will it play out on the show?

• Francesca Bridgerton marries John Stirling, the Earl of Kilmartin, in "Bridgerton" season three.
• But the show makes a major creative choice at the end of the season that will deeply affect her story.

Warning: Major spoilers ahead for "Brigerton" season three and the book "When He Was Wicked."

"Bridgerton" season three wrapped up Penelope and Colin's love story — but its finale set up a revelatory future for Francesca Bridgerton that's a major divergence from the books.

For those who have been praying for one of the Bridgerton siblings to get a queer storyline, season three delivered. Benedict Bridgerton experienced his first kiss with a man via a threesome with his paramour, Lady Tilley Arnold. But perhaps more shockingly, the show has staged a queer romance for Francesca, one that promises a deviation from her novel "When He Was Wicked."

By the end of season three, Francesca has finally married John Stirling, the Earl of Kilmartin. At the end of the season, at a ball hosted by Penelope Featherington's sisters, she finally gets to meet another member of John's family — his cousin, Michaela Stirling, played by Masali Baduza.

Book readers will note this as a significant change: In Quinn's novels, Michaela is actually Michael, John's cousin and a close friend of Francesca's after their marriage. He's also Francesca's eventual love interest after John dies suddenly two years into his marriage with Francesca.

"Bridgerton" doesn't really mince glances in the finale. Francesca is immediately visibly attracted to Michaela, tripping over her words as they meet and even briefly forgetting her own name. Even if you haven't read the books, the implication is clear — Francesca is going to fall in love with this woman.

"Bridgerton" has made some significant changes to Quinn's novels in the past — most notably, it asserted Queen Charlotte's Blackness, and takes place in a version of Regency-era London where people of color can hold titles. But three seasons in, it has yet to meaningfully change any of the siblings' love stories, making a divergence of this level unprecedented.

Showrunner Jess Brownell told Glamour that Francesca's story, and feeling of otherness, resonated with her as a queer woman and lent itself to this kind of change.

"I felt like there was fertile ground thematically in her book to nod toward telling a queer story," Brownell said.

It's notable that 'Bridgerton' has seemingly committed to a queer romance

"Bridgerton" has previously dabbled in queer relationships, but only between men. In season one, Benedict befriends an artist named Henry Granville, who's engaged in a secret relationship with another man. Granville is married and tells Benedict that he and his wife have an understanding that allows him to pursue the relationship — though only behind closed doors.

More prominently, in "Queen Charlotte," the king and queen's footmen, Reynolds and Brimsley, are also in a secret relationship that appears to have dissolved by the time they reach adulthood.

"Because of the world they inhabited, it was still a hangable offense to be gay, and it was just not possible," Hugh Sachs, who plays older Brimsley, told Vulture.

The rules between men and women differed at the time: Sodomy was a capitol offense in England until 1861, per the Encyclopedia Britannica, while lesbian sex acts didn't fall under any legislation. Obviously, "Bridgerton" is far from historical text, but it seems unlikely that an open, romantic relationship between two women would fly even in the show's alternate history. The show won't be able to write a romance between Francesca and Michaela without actively engaging with what it means to pursue a relationship with another woman in high-society Regency London.

That doesn't preclude their happiness though, according to Brownell.

"There are also some elements of her story that allow us to make sure we can tell a pretty happy ending for Francesca and Michaela," Brownell told Glamour. "It was important for me in telling a main queer story for us to be able to give them a happily ever after, as we have with every other couple."

Changing Michael to Michaela has other major plot implications

In "When He Was Wicked," Michael is forced to reluctantly assume John's title as Earl after Francesca miscarries, preventing it from passing on to one of John's sons. To make matters worse, he's also been in love with Francesca since they first met and does his best to conceal that through cultivating a rakish reputation. After John's death, he flees to India for four years, leaving Francesca to manage the Kilmartin estate.

"Bridgerton" has gone to great pains to remind us that women cannot inherit titles, especially in season three. Inquiries from the Crown leave the Featheringtons scrambling to produce a male heir (congrats to Penelope on winning that race), and the Mondrich family inherits the Kent estate after their young son miraculously turns out to be Lady Kent's closest male relative.

Michaela won't be able to inherit John's Earldom, nor presumably be able to sequester herself in India for years at a time, after his death. And as a presumably unmarried woman herself, she'll likely be facing pressure to marry, or living life as a spinster.

That doesn't mean that "Bridgerton" can't make adjustments to clear a thoughtful path for Francesca and Michaela. In the books, Francesca decides to pursue a second marriage after John's death not out of a need for companionship, but rather because of her desire for children. In fact, she's rather secure in her position as a widow, afforded the rare freedom to live an independent life as a woman. Should she not miscarry and give birth to John's son in the show, she would retain that freedom without question of which man would assume the title.

Brownell told Glamour that despite the change from Michael to Michaela, she still plans to "honor" the book on television.

"Obviously, some changes will have to be made to the storyline, but there are ways to honor a lot of the book," Brownell said.

At this point, we can't be certain of how "Bridgerton" will manage Michaela's gender swap, and her eventual romance. But for this gentle writer, it's heartening to see "Bridgerton" take a big swing like this — and set up a sweeping queer love story for one of its main characters.