Spoiler alert: This story includes details of the first four episodes of Netflix's "Bridgerton" Season 3 (now streaming).

NEW YORK ― Netflix's "Bridgerton" has many things going for it, but the one thing that leaves viewers swooning every season is the spark between the leads. We're talking hot, passionate kisses, burning gazes and electric touches.

The romance between Season 3's leads Penelope Featherington (Nicola Coughlan) and Colin Bridgerton (Luke Newton) has been brewing for a while now, and fans of the novels by Julia Quinn were rooting for their turn. Ever since the first four episodes of Season 3 began streaming May 16, "Bridgerton" stans cannot stop talking about the "Polin" (as fans affectionately call them) carriage scene, in which the two first become intimate.

"When I read the book four years ago, that was the scene that stood out to me," Coughlan tells USA TODAY, shortly after the new season's world premiere. "I remember us talking about it in one of our very first meetings and we were reading (that) he grabs her boobs.

"We were, like, in fits of giggles, but at that point we had no idea (if) we would ever get to that story," Coughlan says.

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But when Season 3 rolled around and Coughlan learned the scene would be included in the series, she was very nervous.

"You just don't want to mess it up, you know?" Coughlan says. "But I just love that scene so much, because it's romantic. It's suspenseful. It's sexy. It's funny. It's heartfelt. You feel that true intimacy and connection between them."

Coughlan adds that she loves how the scene, a turning point in Penelope and Colin's relationship, was shot. "It's so well done," she says. "I loved that the cameras (were placed) outside (the carriage) because then it just feels all the more intimate. Really, it's just this moment between these two characters."

The moment when Colin realizes he's in love with Penelope

Penelope has secretly crushed on her childhood bestie and neighbor for years, and Colin ― who is a bit of a fool, as Lady Whistledown might say ― has been mostly oblivious to her feelings, a fact that he makes more than clear when he told his friends last season that he would "never dream of courting Penelope Featherington." Unfortunately for him, Penelope overheard the conversation and cut him off. To make amends and get back into her good graces, Colin offers to help Penelope become charming and confident so she may secure a husband this season.

However, once he starts teaching the art of flirting to Penelope and sees her blooming, it doesn't take him long to realize that he has feelings for her.

What was the moment that Colin decides that he's in love with her: The time she bandaged his cut hand? Or when the two kissed for the first time? Or every time he sees her with Lord Debling, (Sam Phillips) an eligible new suitor on the hunt for a wife?

"I think it's when they have their first kiss," she says. "He's always had love for her, but in that moment: It's so brilliantly done. Because sometimes you kiss people and you feel nothing, and then you kiss someone, you're like, why is my whole body electric? What's going on? He has that moment with her."

While Colin's feelings may have taken a turn at that point, Coughlan says the moment felt like an end for Penelope.

"It's really sad, because she thinks that's the end," Coughlan says of the kiss. "She's like, I've just embarrassed myself. I've just told him that I want this. I've asked him to kiss me, and he's done it. How embarrassing. And she runs away. He goes, 'Oh'."

But Penelope could not have been more wrong, because that kiss sets the wheels in motion for a declaration of love that had the internet weak in the knees.

Penelope's glow-up

Colin's glow-up may have been the talk of the ton, awarding him the status of an eligible bachelor, but Penelope's own glow-up is no less scintillating. She ditches the yellows and citruses her mother made her wear, opting for softer and fresher colors, and changes her hairstyle, taking inspiration from the "girls in France".

Penelope's big "She's All That" moment in the season premiere, in a shimmery green dress, had the ton buzzing and took months to prepare.

"That look was months of people planning," Coughlan shares. "How it would move, what it would be. We need a dress that could be ripped and then the skirt had to be replaced. But even the hair and makeup that was months of finding the right style even like down to the tiniest of details."

Coughlan says the idea behind the look was to "go like a little too strong first, because (Penelope) doesn't have the inner confidence to inhabit that look at all."

However, when she's mocked for her new look and resident mean girl Cressida Cowper rips her dress, "she pulls back a little," and in the next episode we see her in more muted tones.

"The idea behind it was that she she's always wanted to dress like this. She's a real romantic but she doesn't want to be the one that's really standing out," Coughlan says.

Which Bridgerton sibling is next?

"Bridgerton" producers haven't followed Quinn's chronology, switching things up to surprise audiences. While fans are reveling in the new season, there is also anticipation about which Bridgerton sibling will take the lead next season. Will it be the free-willed Eloise (Claudia Jessie) or the second-born son Benedict (Luke Thompson)?

"I don't know anything," Jessie says. "But I'm going to be so brokenhearted when I have to stop playing Eloise. I just want to be here as long as I can."

But for now, all eyes are on Season 3's classic "friends to lover" storyline, in which one falls first but the other falls harder. Nicola would have probably not done it any other way because the trope is her personal favorite.

Coughlan and Jessie both say things are going to get "serious" and a "real mess" between Penelope and Eloise in the second half of this season (streaming June 13) given all that has been simmering between the two.

Will Colin find out that his lady love is the person behind Lady Whistledown? And should he?

"Well, yeah, of course she should" tell him, Coughlan says. "I think when you love someone truly, you have to reveal all of yourself, which is hard."

Saman Shafiq is a trending news reporter for USA TODAY. Reach her at [email protected] and follow her on X @saman_shafiq7.