Millie Bobby Brown and David Harbour reportedly clashed on the set of Stranger Things.

According to The Daily Mail, Brown — who plays Eleven on the show — formally complained about Harbour (who plays Eleven’s adoptive dad, Jim Hopper) before the costars reunited to film the fifth and final season of Stranger Things.

The Enola Holmes star “filed a harassment and bullying claim before they started shooting the last season,” a source told the outlet, adding that “there were pages and pages of accusations” and that the subsequent investigation “went on for months.”

The outlet also alleged that Brown — whose claims against Harbour reportedly did not include any allegations of misconduct of a sexual nature — had a representative on the set of season 5, which wrapped filming in December 2024.

Reps for Netflix, Brown and Harbour have not responded to requests from PEOPLE for comment.

As their father-daughter relationship became more tumultuous onscreen, Brown spoke about how their real-life relationship mirrored that of their characters.

“We went through so many different emotions… we get angry at each other, we are like father and daughter,” the then-14-year-old actress told the crowd in 2018 at PaleyFest in Los Angeles, according to Refinery29.

“We got angry at each other,” Brown continued, adding that she and Harbour “would express our feelings on and off the set, and… those scenes were so raw and real that the reward is the scenes.”

Harbour has also previously hinted at the actors’ on-screen relationship bleeding into real life. In 2021 he said that he has a “deep fatherly affection” toward Brown, whom he first met while filming season 1 of Stranger Things, which premiered in 2016.

“Millie and I have always had sort of a special relationship because I knew her when she was so young. I knew her before any of this big fame hit,” Harbour said on the That Scene with Dan Patrick podcast.

“I have a real protective feeling for her. I have a real, like, worry,” he said of Brown, who was 11 when she first started working on the Netflix show. “I worry about her and the fame and all that she has to struggle with. And I’ve just always felt this kind of deep fatherly affection for her.”

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Stranger Things season 5 premieres with Volume 1 on Nov. 26 at 8 p.m. ET, followed by Volume 2 on Dec. 25, and the finale on Dec. 31.