This post contains spoilers from Bridgerton‘s second season.

Bridgerton stars Nicola Coughlan and Claudia Jessie are just as shocked about that season 2 finale as we are.

Speaking with PEOPLE ahead of the highly-anticipated second season premiere, Coughlan, who plays Penelope Featherington a.k.a. Lady Whistledown, and Jessie, who portrays Eloise Bridgerton, opened up about Eloise discovering Whistledown’s true identity and what that means for their friendship moving forward.

“I was really shocked about it,” Coughlan, 35, said. “We didn’t know that it was going to happen. We only got the scripts incrementally.”

“There was a certain incident that Penelope would say to Eloise like, ‘You can’t lie to me,’ and I was like, ‘Oh, I’m not sure about that line there,’ and they would go, ‘You really have to say it because it’s leading to something,’ ” she recalled.

“And then we went, ‘Oh no, it’s not leading to that. Is it?’ Because Claudia and I talked about it all the time. We were like, ‘When that happens, it’s going to be awful. It’s going to be horrendous.’ Claudia and I were absolutely heartbroken by the thought of it,” the Derry Girls actress added.

“My heart was beating so hard during that whole final episode,” she concluded. “I felt sick. I’d forgotten a bunch of it, too. Because I filmed a lot of the final episode in my final two weeks.”

Jessie felt just as shocked, but hopeful for what’s to come.

“I hope they make friends again very quickly,” said Jessie. “Once they do make up, I think it will mature their friendship, because you kind of have to have a bit of a falling out, especially when you’re so young. Because they’ve had this friendship since they were children, they love it, they’re so easy, but I think it’s important for them as they’re growing to have a bit of a fallout and a tumble, because it’s going to deepen their bond.”

The star shared, “I think they’re going to have an understanding. I also think, as well, that Eloise is going to be a very good friend and not tell anyone else that Penelope is Lady Whistledown. I really predict that that’s what they’re going to do. I think she’s just going to continue to be a very good friend, even though she might not be ready to talk to Penelope.”

While season 1 centered around Daphne Bridgerton (Phoebe Dynevor)’s love story with the brooding and mysterious Duke of Hastings, Simon Basset (Regé-Jean Page), the second season will be all about her brother Anthony Bridgerton (Jonathan Bailey)’s quest to find his viscountess, with several new faces joining the cast (though one, in particular, is not returning).