Millie Bobby Brown Called 'Stranger Things' Costars To Make Sure They Didn't Have Beef

Millie Bobby Brown wasn't just saying goodbye to "Stranger Things" -- she was making sure she wasn't losing her TV family too.

The actress revealed during a discussion with "Happy Sad Confused" podcast host Josh Horowitz at 92nd Street Y she called "all" of her castmates -- which includes Noah Schnapp, Gaten Matarazzo, Finn Wolfhard, Joe Keery, Sadie Sink and Caleb McLaughlin -- after filming wrapped ... just to make sure they were all still cool.

Millie admitted they probably thought she'd gone a little crazy, but she wanted to hear they weren't about to stop talking. She even apologized in case she'd ever upset any of them, telling the cast they were basically her siblings.

And, honestly, can you blame her? She spent nearly a decade playing Eleven after "Stranger Things" first started filming back in 2016.

Millie also got real about how hard it hit her when it was all over, saying she cried through all of January and even slipped into a slight depression -- something she never saw coming because she's usually such a happy-go-lucky person.