Millie Bobby Brown and Caleb McLaughlin are revealing what their relationships are like behind the scenes

The Stranger Things kids have been to the Upside Down and back together, so it’s no surprise they’ve become an incredibly tight-knit group.

On Sunday, the show’s cast and creatives gathered at the PaleyFest panel in Los Angeles to discuss the Netflix series’ booming success — and how they’ve become like family behind the scenes.

Asked how they got to know each other, 16-year-old Caleb McLaughlin said he and his fellow child stars — Millie Bobby Brown, Finn Wolfhard, Gaten Matarazzo and Noah Schnapp — clicked pretty much instantly.

“I feel like once we all met each other, we were all very outgoing so it was just easy to connect,” he said. “The second day it was like, ‘Oh, we’re friends.’ ”

“It was like a relationship, actually, because it felt like we went through a honeymoon stage,” added Millie, 14, with a laugh. “All of us. We would be like, really nice to each other — we didn’t want to do anything that would hurt each other’s feelings.”

According to Caleb and Millie, their friendships are “so different” now — in fact, they feel like “siblings.”

“We are actually siblings — we argue all the time,” Millie said.

“I wouldn’t say all the time,” Caleb hedged.

“Yeah, we do!” she responded. “About food, come on.”

“It’s about the remote control — like, who-gets-the-remote-control arguments,” he joked.

“Yeah. Like, ‘Why are you eating my chips?’ Things like that,” Millie explained. “And Sadie [Sink] doesn’t argue. She’s like, ‘Guys, everyone calm down.’

The Paley Center For Media's 35th Annual PaleyFest Los Angeles - "Stranger Things" - Inside
From left: Millie Bobby Brown, Caleb McLaughlin and Sadie Sink
| Credit: Frazer Harrison/Getty

PEOPLE also caught up with executive producer Shawn Levy, who opened up about how the series is evolving as its cast grows up.

“We realized early on we’re not going to stop time,” he said. “So we’re not going to pretend that these kids are still 12. We’re going to create and dramatize stories that meet kids where they are and that are honest about where they’re at. Season 2 was about the desire to return to normal. Season 3 is about change, the inevitably of change — change is coming for Hawkins, and change is coming for these characters, whether they like it or not.”

So does that mean more romantic relationships will inevitably start to form?

“I’m not going to say too much,” he said. “There’s definitely new love — whether or not it’s in a love triangle, I don’t want to say.”

A premiere date for season 3 has not yet been announced.