A hot new diamond has entered the ton. 

Bridgerton revealed that it has officially started production on season four of the Netflix series, sharing new photos of this season's leads Luke Thompson and Yerin Ha. In the pics, Luke and Yerin appeared to be channeling their characters Benedict Bridgerton and Sophie Baek, posing together on the streets of London. 

"Esteemed members of the Ton," the show posted on Instagram Sept. 16, "it is with great joy that we inform you that Bridgerton Season 4 is officially in production!"

And fans were quick to share their excitement about the news—especially as it was their first look at the costars in character as their television roles. 

"OH MY GOOOOOOOOD LOOK AT THEEEEEEEEM," one fan wrote in the comments. Another added, "Ok, I'm crying in the middle of a class."

One user noted that she is ready for the new storyline, writing, "Well, I… am speechless. I thought I was completely obsessed and couldn't leave S3 but hello Benedict and Sophie."

After Penelope Featherington (Nicola Coughlan) and Colin Bridgerton (Luke Newton) helmed season three, Luke's Benedict was announced as the show's new romantic lead in July, with season four based on Julia Quinn's An Offer From a Gentleman, the third Bridgerton book. The story follows Benedict as he meets a mysterious lady in silver—the one and only Sophie—only to find her again two years later, unaware that she is the woman he has spent all that time pining for.

And Luke, 36, is looking forward to exploring the dynamic between the characters inspired by Cinderella, as Yerin's Sophie is the victim of very tragic circumstances.

"What's striking about season four is that it's the struggle between a proper old-school fairy tale," Luke told Netflix's Tudum. "The romance of it, and the actual reality of the world."

He continued, "And both are true. You have to hold both of them—the romance and the reality—in your hand. In its best version, ‘true love' happens in the middle of that."

Yerin, 29, added that she has very much appreciated the "playful, freeing, therapeutic" feeling of getting ready for the season alongside Luke, sharing that the two first met at showrunner Jess Brownell's house for dinner.

"I remember Luke stood there with arms wide open, just ready for an embrace," she told Tudum. "That was the moment I was like, ‘Ah, OK, I don't need to stress about these little things now. I can just genuinely focus on the on-screen connection with him.'"

She also explained that she's especially interested in playing a character that has so much she's trying to overcome.

"What drew me to Sophie was that she immediately has obstacles," she added. "Whether it's this battle around social status or trying to hide her feelings from Benedict."  

And luckily for Benedict, he won't be navigating the marriage market alone, as Jonathan Bailey confirmed he'd be returning this season to play eldest brother Anthony Bridgerton.

"Obviously being the older brother," Jonathan shared on Good Morning America in August, "I'm gonna be there to support the youngsters as we go."

But how does he think Luke will handle leading man duties? Jonathan knows he's "gonna be stunning."

As you prepare for season four, take a look back at season three of Bridgerton with a deep dive into everything that was changed from book to screen.

In Netflix's version, Penelope Featherington (Nicola Coughlan) becomes our heroine, deciding that at only 19 years old it's time to give herself a full makeover in an effort to shed her wallflower ways and find a husband. To that end, she nixes the yellows and oranges she's worn for most of seasons one and two, instead opting for more flattering dresses and colors—oftentimes wearing the famed Bridgerton blue. Pen also gets help from Colin Bridgerton (Luke Newton), whom she has had a crush on for years, on how to improve her flirting techniques.

The circumstances are very different for book Penelope, who is already 28 years old in Romancing Mister Bridgerton, since the story is set in 1824, 10 years after Anthony Bridgerton (Jonathan Bailey) married Kate Sharma (Simone Ashley). Book Penelope is considered an old maid and her fashion transformation stems more from her mother finally leaving her alone after she doesn't get married. While book Pen is also stressed about being stuck with her mother for the rest of her life, it does not prompt her to find a husband.

Another major difference? No one—not even the reader!—knows that she's town gossip Lady Whistledown at the beginning of the book, a secret that only comes to light until about halfway through the fourth book; Netflix viewers, meanwhile, were treated to that bombshell in season one. 

Colin is our dashing young suitor in season three, and as has been the case for his character throughout the show, book Colin's trajectory is different from show Colin.

In the book, he is 33 years old and has been traveling extensively for years—as opposed to just a few months in the show—rarely leaving him at home. He also finds himself struggling to find his purpose, which he's slightly less concerned about on the show.

Much like on Netflix though, he finds his attraction to Penelope slowly growing throughout the book and spends much of his time marveling at just how kind, funny and stunning Pen is—all qualities he's shocked that he and the rest of the ton never noticed before.

In both the book and the show, emotions really come to a head for Colin and Penelope when she accidentally on purpose reads his travel diaries. Book Pen was visiting the Bridgertons because she's still best friends with Eloise Bridgerton (Claudia Jessie), while show Pen was at their house in episode two for private flirting lessons with Colin.

In both versions, Colin cuts his hand, although in the book it's on a letter opener and in the show it's because of a broken candle holder.

Regardless, it's as she is wrapping his hand that Colin really notices Penelope.

For Polin, in the book and show, their first kiss comes when Penelope directly asks him to lock lips, telling him she'll live her life having never been kissed if he doesn't do it.

On our TV screens, the moment occurs at the end of episode two, just after it's been revealed to all of the ton that Penelope asked for Colin's help in finding a suitor.

In the book, the kiss occurs in the Featherington drawing room when Colin visits Penelope to express his distress over the fact that he thinks his sister Eloise is Lady Whistledown (voiced by Julie Andrews).

Yes, in both the novels and the screen adaptation, Colin and Penelope's second kiss happens in a carriage just before he FINALLY proposes.

Netflix decided to make the kiss and proposal happen in the Featherington carriage at the end of episode four, just after Colin has ruined Penelope's chances with Lord Debling (Sam Phillips).

He doesn't yet know that she's Lady Whistledown, basically the Regency era DeuxMoi. In fact, episode one ends with Colin expressing his hatred for Lady Whistledown after she wrote some not-so-nice things about his "new" personality following his travels, telling sister Eloise that he will ruin whoever Whistledown really is.

In the book, Polin's carriage kiss and engagement occurs in Colin's coach after he's followed Penelope into town and learned her shocking secret: that she is, in fact, Lady Whistledown, meaning he goes into their marriage fully aware of her double life.

Francesca Bridgerton (Hannah Dodd) is unfortunately sometimes considered the forgotten Bridgerton child, not because her family doesn't love her, but because—as she does on the show—the sixth Bridgerton sibling prefers quiet and calm.

In the book series, it's casually mentioned that Francesca found her husband seven years before we pick up with Penelope and Colin. However, executive producer Shonda Rhimes and team have decided to combine some of the book plotlines with Francesca, Colin and Benedict Bridgerton (Luke Thompson) all searching for love in season three. That leads us to…

In the TV show, Francesca becomes Queen Charlotte's (Golda Rosheuvel) "diamond" of the season and finds herself being courted by the Queen's pick Lord Samadani (David Mumeni), as well as by her preferred suitor, John Stirling, Earl of Kilmartin (Victor Alli). (Sadly, Queen Charlotte is not a character in the books, meaning the monarch—and her truly fantastic headpieces—never anoints a "diamond" of any season.)

But luckily for her, she and John find the ideal partner in one another and enjoy a small wedding at home, something book readers don't get to experience. The couple then move to Scotland, where their story will continue to play out. We'll avoid any spoilers about Francesca's future, but if you are interested in spoilers, her story is expanded upon in the sixth Bridgerton book, When He Was Wicked.

Those who have only watched the show might be surprised to learn that by the time Colin and Penelope get together in the books, Benedict has already been married for seven years and is quite a successful artist (book three, An Offer from a Gentleman—which Netflix skipped in favor of book four—tells his love story).

On the show, however, he is still trying to find his way in life as the second Bridgerton son, avoiding marriage and instead hooking up with a sassy widow, Lady Tilley Arnold (Hannah New) and her friend Paul Suarez (Lucas Aurelio). Viewers will have to see how his plotline unfolds in a potential fourth season.

Eloise has a very different storyline on the show, namely that she is no longer friends with Penelope after she found out that Pen is Lady Whistledown. Eloise is instead BFFs with the ton's biggest bully Cressida Cowper (Jessica Madsen) after they bonded in the countryside. And when she learns that Colin and Penelope are engaged, she's upset, thinking that Pen used their friendship to get to Colin. It's not until the end of the season when she realizes how much she misses Penelope's friendship and the two are able to come together once again.

As for book Eloise, like book Penelope she is also 28 years old—but unlike her double agent friend, Eloise has turned down six marriage proposals. And when she learns about Colin and Penelope, she could not be more thrilled for the two of them. Throughout Romancing Mister Bridgerton, there are also hints at Eloise's future, which gets its due in book five, To Sir Phillip, With Love.

As for her new best friend Cressida, while the show sees her still unmarried, in the book she is already a widow and still a nuisance to Colin and Penelope. But more on her in just a moment.

The nature-obsessed Lord Debling is the ton's latest eligible bachelor this season—and the apple of Cressida Cowper's eye. Yet, he is a character purely created for the show and mainly acts as the catalyst to help Penelope come out of her shell, but, more importantly, to finally bring Colin and Penelope together.

Unfortunately, as much fun as it was to watch Colin save Penelope's life (with an assist from Lord Debling), the balloon event—and the very awkward conversation about birds—was purely made up for the show.

One of the biggest changes for the Featheringtons is that the show has done away with Felicity, the fourth Featherington daughter, who is the sister Penelope is closest to, and also Hyacinth Bridgerton's (Florence Hunt) best friend.

In the books, Mrs. Featherington (Polly Walker) considers Felicity her last chance at a great match for one of her daughters, even suggesting that she should marry Colin. The book Featheringtons are also dealing with less money troubles, as Penelope has been secretly pulling from her Whistledown funds for the family with the help of their solicitor, who, interestingly enough, was the person in the books who encouraged her to write her column and helped set up everything she needed with the publisher and a bank account.

As for sisters Prudence (Bessie Carter) and Phillippa (Harriet Cains), while on the show they are in a race to see who can have a baby boy first and continue the Featherington line, in the books they're less involved and are married to totally different characters.

Show Prudence is married to Harry Dankworth (James Phoon), while in the book she is married to a man named Robert Huxley. As for Phillippa, she is married to Albion Finch (Lorn Macdonald) in season three, whereas in the books she married Nigel Berbrooke (whom you might remember as one of Daphne's ill-mannered suitors in season one).

In both the book and the show, Violet Bridgerton (Ruth Gemmell) is busy finding partners for her unmarried children. Book Violet has also long moved out of the Bridgerton house, and now lives at what the family loving calls Number Five (as they joke they couldn't come up with a better name). And while author Julia Quinn never gives a glimpse of Violet's life after all her children are married, season three hints at a possible romance for the Bridgerton matriarch with Lady Danbury's (Adjoa Andoh) brother Lord Marcus (Daniel Francis)—who does not exist in the books.

Another difference in the Bridgerton family? Youngest siblings Hyacinth and Gregory (Will Tilston) are much older in the fourth novel—with Hyacinth enjoying her first season and Gregory finishing his final term at Cambridge University—while the show finds them still in the background as their older siblings have the drama for the time being. However, we might be hearing more from them in future seasons, as Hyacinth's love story is told in book seven, It's in His Kiss, and Gregory's is book eight, On the Way to the Wedding.

A small change from book to screen is that, in the book, following Colin's proposal, he and Penelope actually go to the Featherington family's home to share the news with her loved ones. Hilarity ensues as Mrs. Featherington assumes he's there to see her daughter Felicity, before Colin doubles down on wanting to marry Pen and even defends how wonderful she is to her mother (something with obviously makes Penelope swoon).

On the show however, the couple first make their way to the Bridgerton household where everyone is thrilled—except for Eloise, who is upset that Penelope hasn't told Colin she's Lady Whistledown.

The book does not include much information about Colin and Penelope's wedding, only saying that it was a small affair and that the couple was able to move the date up by a few weeks after Colin not so subtly let Lady Bridgerton and Lady Featherington know that he and Pen had been…intimate with one another.

As mentioned, in Romancing Mr. Bridgerton, Colin learns Penelope's secret before he proposes to her. And while he is furious she kept it from him, he is both impressed and slightly jealous that Pen has done something so extraordinary with her life. However, he does truly want her to stop writing, a problem that comes to a head when Penelope's issue saying Cressida is not Whistledown is published during her and Colin's engagement ball. But book Colin is able to make peace with Penelope's secret, and actually take an active role in helping her reveal it (more on that in a moment).

Show Colin, however, has a much more difficult time reconciling the fact that he loves Pen, but truly hates Lady Whistledown. In fact, the couple spend much of the second half of the season apart as Colin deals with his emotions on the matter.

Throughout Romancing Mister Bridgerton, Lady Danbury is trying to figure out who Lady Whistledown is and even offers a £1,000 reward to whoever finds her. In the show, the reward comes from Queen Charlotte herself, who instead offers a £5,000 reward.

In both cases, before Penelope's identity is revealed, Cressida comes forth claiming to be Lady Whistledown in order to secure the reward. In the book, Cressida has been left without much funds following her husband's death, and is hoping to take the prize money.

As for show Cressida, her circumstances are a bit different, with her parents planning to marry her off to an elderly nobleman. She believes that coming forth as Whistledown will secure her the £5,000 so that she can avoid marriage.

The way Penelope's secret is revealed differs wildly from book in the screen, however in both versions Cressida is able to figure out the truth and hopes to blackmail Penelope into giving her £10,000, or she'll reveal the secret to everyone. In the book she finds out it's Penelope because Pen uses the same turn of phrase in real life as she does in her issue of Whistledown decrying that Cressida is the author. On the show, she learns Pen's secret from a printing shop apprentice.

But how does the ton find out? In the book, Colin takes over sharing the news and does so at sister Daphne and her husband Simon's giant ball. He makes a grand show of telling the guests how much he loves his wife, before revealing Penelope's identity. But as he planned, both Anthony and Simon immediately throw their support behind Penelope and the guests have a hard time staying mad at her.

On the show, however, Penelope takes matters into her own hands, inviting Queen Charlotte to her sisters' ball before going before the ton and pleading her case, in the hopes that the Queen will show her favor, which very luckily, she does.

The eldest Bridgerton sibling Anthony and his wife Kate had their love story told last season—based on the book The Viscount Who Loved Me—and the biggest changes for the new couple from book four to season three is that they're newly married, still living with Anthony's mother in Bridgerton house and expecting their first child together, unlike the books in which they've already been married for 10 years.

And the newlyweds are besotted with each other, which is luckily something found both on the show and in the book.

Former boxer and gentlemen's club owner Will Mondrich (Martins Imhangbe) and his wife Alice Mondrich (Emma Naomi) do not appear in the books, but they have quite the compelling storyline in season three, including their new introduction into society, as well as Will selling his club to appease the ton.

Fans of the show may be surprised to learn that book four is the final time we hear from Lady Whistledown in the Bridgerton series. After her identity is revealed, Penelope decides that writing as Whistledown for almost 12 years is long enough, so she officially retires.

On the show, however, Penelope continues writing, but does so under her own name.