Ginny & Georgia‘s pregnancy love triangle twist wasn’t just a surprise to fans — the cast also didn’t see it coming.

During the season 3 finale, which premiered via Netflix on Thursday, June 5, Georgia (Brianne Howey) dealt with her new normal after a murder trial — and with her marriage to Paul (Scott Porter) coming to an end. The last scene showed Georgia drinking milk, which her daughter, Ginny (Antonia Gentry), realized was a craving her mother only had when she was pregnant.

The twist? It’s unclear whether Paul — or love interest Joe (Raymond Ablack) — is the dad.

Porter, 45, exclusively told Us Weekly that even he doesn’t know the paternity of Georgia’s baby and revealed the cast “didn’t even know about” cliffhanger until the table read.

“We were reading the script, and at the very end, there is the addendum of her drinking the milk. The words, ‘Mom, you only drink milk when you’re pregnant,’ [were] not in the script. That was a late add,” Porter revealed to Us. “So I think all of us — even until the last moment — didn’t even know necessarily what all of it meant. That’s just how it is on the show. We got to keep everything buttoned up and everything under wraps, so I know zero about what’s going to happen.”

This doesn’t come as a surprise considering many of Porter’s colleagues have told Us the same thing about not knowing what to expect.

“When we entered the season 4 writers’ room, I knew unequivocally without a doubt whose baby it was,” creator Sarah Lampert exclusively told Us. “I came into the writers’ room and I said, ‘Here’s whose baby it is. Change my mind.’ The writers’ room is phenomenal. Our writers are fantastic and truly it’s such a kinetic, live and ever-morphing thing.”

As a result, the decision potentially shifted along the way. “That’s what makes the show good is it really becomes alive at every stage of the process. But certainly in the writers’ room. So it wasn’t decided,” Lampert revealed. “They’ve changed my mind before. I’ll put it that way.”

She concluded: “Oh, [we were] utterly divided. We went back and forth and back and forth. It was a full-on school debate effort. It was phenomenal because there’s pros and cons story-wise to both — but there’s one clear answer and I’m not going to say what it is.”

Ablack, 35, is rooting for his character, Joe, telling Us, “In my heart, Joe is the father. But I don’t know. I have no idea. I’m as eager for episode 1 of season 4 as everyone else is to find that truth.”

As for Porter? His biggest concern is whether Paul would even believe Georgia after she lied about being pregnant earlier in the season.

“It’s one of those ‘fool me once, fool me twice’ situations here. I think Paul is going to think long and hard about anything else that comes out of Georgia’s mouth,” he said. “It’s really heartbreaking that that’s the case. He asked her for so long to let him in, to just be honest with him and now it’s to the point where he can’t believe a word she says. That’s just heartbreaking to me.”

Ginny & Georgia is currently streaming on Netflix.