Millie Bobby Brown & David Harbour's Onscreen Spats Weren't Entirely Fake

As an audience, we love to cling to the idea that our favorite actors in our beloved series are just as close in real-life as they are on screen. With such a strong need for this to be true, we are quick to forget that the roles of performers aren't a perfect reflection of their behind-the-scenes connections. Millie Bobby Brown and David Harbour's recent spat proves just how much we don't know about the acting co-stars. As season 5 of their series is set to air in 2025, headlines reported that Brown filed a complaint for bullying and harassment against co-star Harbour. However, Brown hinted at a clash with the "Hellboy" actor in 2018. 

"We got angry at each other, we would express our feelings on and off the set," Brown told PaleyFest audiences (via Refinery29) about acting with the "Thunderbolts" actor. Before too long, a similar tale of their relationship behind the scenes was echoed in a worrying remark from Harbour in a 2019 interview (via Yahoo!Movies). "I care about her a lot and I think she's making some good decisions and some bad decisions, and I'm very able to voice that to her and she's very able to argue back with me," before later adding a habit of his young co-star that bothers him, "And she's very interested in my romantic life too, which I'm annoyed by to no end." 

Maybe David Harbour's opinions on Millie Bobby Brown's choices got to be too much, or maybe, as the pair have gotten older, time has spoiled a relationship forged on set. Either way, bad blood has boiled over, with reports of a complaint filed in 2024 when "Stranger Things" season 5 was in production. The case was developed by Brown, who claimed that Harbour was bullying and harassing her while on set. It's been clarified that the alleged behavior was nothing of sexual nature but created an uncomfortable environment for the "Enola Holmes" star. 

Over the course of her time on set, Brown was supposedly able to compile pages worth of proof that support her claims against the "Thunderbolts" actor. In response to her concerns, Netflix was said to have launched an internal investigation that lasted months, examining the behaviors on set. Though Netflix has not openly commented on this case, it was revealed that by December 2024, the Florence by Mills founder had a representative that accompanied her while she was on set. Since news of the complaint released in November 2025 by Daily Mail, Netflix, Brown, and Harbour have not addressed the claims publicly. But the revelation that Brown underwent critical and cruel treatment from a co-star she once admired is a tragic experience for the "Stranger Things" actor.