Sienna Miller‘s character in HBO‘s War, glamorous movie star Carla Duval, has been a little bit messy from the jump, but she does something in tonight’s all-new episode that is absolutely bonkers.

**Spoilers for War Episode 4 “Sing,” now streaming on HBO Max**

She kisses Johnny Warren (Archie Renaux), the handsome, young, and very-not-single lawyer helping out on her divorce case. Even worse? Carla has no idea that for all his sweet-talking and moral support, Johnny is secretly working as a mole at Taylor & Byrne, leaking important top secret info to the Cathcarts & Sons, the prestigious law firm representing Carla’s ex-husband Morgan Henderson (Dominic West).

The kiss in question happens at the very end of War Episode 4 “Sing,” when Johnny comes to Carla’s home to get her to sign the documents that will push her already heated divorce into litigation. Serena Byrne (Phoebe Fox) and Nicholas Taylor (James McArdle) have discovered that Morgan is hiding assets, making his $110 million settlement offer a pittance compared to the billions they believe Carla is owed.

For her part, Carla confesses it’s like she doesn’t even know her ex and dreads the media frenzy she and her teen son Gabriel (Aran Murphy) endure by going to court.

Johnny gives her a pep talk: “Carla, look. They want to get you what’s right, what’s fair. That’s the plan and no settling. Yes, it’s a fucking nightmare, but you go in there with [Celia Imrie’s] Budgie, you get what you deserve, and then you and Gabriel are set for the rest of your lives.”

“Why are you the one talking like this?” Carla asked, focused on Johnny. “Someone so junior.”

Before he can apologize, Carla says, “No, it’s what I want.” Then she stares at the younger man’s lips… and they kiss. A woman who is counting on her husband’s infidelity to be a boon to her in an impending divorce trial kisses the junior associate representing her in the case!

“I don’t think Carla is necessarily thinking about the outcomes of her decisions in that moment,” Sienna Miller told DECIDER. “I think she’s fraught and she’s vulnerable, and he’s attractive and he seems to understand her and intimately know the intricacies of what she’s going through.”

“He’s a good looking ear. I don’t know that you legislate on matters of the heart I think she just jumps in.”

Archie Renaux also told DECIDER that Johnny’s not thinking things through in that moment, either.

“I don’t know, I think maybe there’s a little bit of a fascination with Carla and some sort of empathy there for her as well, what she’s going through,” Renaux said. “I think Johnny’s maybe looking for an outlet and someone to confide in outside of his own relationship, wrongly. I sort of think that’s how it happens is a slight fascination.”

How will this latest indiscretion affect the upcoming divorce trial? Is Carla and Johnny’s kiss a one-time affair?

New episodes of War premiere on HBO and HBO Max on Thursdays at 9 PM ET.