"Stranger Things" star David Harbour almost spilled some details about the show's upcoming fourth season but his co-star Millie Bobby Brown stopped him.

Harbour was on a brief filming break on Wednesday and decided to hop on Instagram to check in with fans of the Netflix show. He kicked things off by saying, "I haven't done Instagram Live in a little while. I think I can only be here for like three and a half minutes because I have to go on set fairly soon. I'm here shooting season four of our television show.

I don't think I'm supposed to be showing you these things. Who wants to hear spoilers for Season 4? Let me just read directly from the script."

stranger things david harbour
David Harbour as Chief Jim Hopper in “Stranger Things." Netflix

Although no official show details were revealed by the actor, he appeared to be in character as Hopper during the stream, wearing a dusty coat and sporting scratches and bloody makeup, Yahoo! reports.

Things took a comical turn when Brown jumped into the Instagram Live and made Harbour break out in laughter. "Oh no Millie, don't tell Netflix, don't tell Netflix that I'm doing Instagram live from set. I'm just gonna read your sections of the script, Millie. I'm just gonna tell everybody what happens to Eleven this season," he said.

Millie then joined in by questioning Harbour's actions. "I'm so crazy. I shouldn't be doing this," he responded.

The actor then jokingly said, "I'm getting fired." Brown reassured him that although he won't get fired there's a chance that he'll receive a phone call from someone at Netflix.

Last year, Harbour told People that Season 4 was his favorite. He also revealed viewers will see an entirely different side to fan-favorite character Hopper.

Harbour's comments come just after his co-star, Dustin actor Gaten Matarazzo, shared that the upcoming episodes would offer more scares.

"That's the one thing that I've noticed," Matarazzo said during a Tuesday appearance on "The Tonight Show." He added, "They're going for it this year. That's pretty cool."

Season 4 of "Stranger Things" does not yet have a release date.