Millie Bobby Brown has insisted that she and her Stranger Things co-star David Harbour recently put on a united front publicly because they've "been doing that for the last 10 years".

Earlier this month, a report claimed that the 50-year-old actor faced an internal investigation after his 21-year-old co-star filed a harassment and bullying complaint against him before filming the fifth and final season.

Days later, the stars surprised onlookers by posing for photographers and laughing and hugging on the red carpet at the Los Angeles premiere of the season.

During an interview with The Hollywood Reporter conducted a few days after the event, Brown was asked why it was important for the co-stars to show a united front amid the accusations.

"We've been doing that for the last 10 years," she responded. "I mean, we have always been united in that. We love this show with everything, and we value our friendship more than anything."

According to the Daily Mail report, which was published on 1 November, Brown's complaint featured "pages and pages of accusations" against Harbour, although no allegations of sexual impropriety, and the inquiry went on "for months".

While the full outcome is unknown, the British actress was reportedly accompanied by a personal representative on set for the season.

Brown has yet to directly address the report, however, she told the publication that it was "so nice" to have so many scenes with Harbour - who plays her character Eleven's adoptive father Jim Hopper - this season after being apart for much of series four.

"I think some of people's favourite scenes of Eleven are Ele and (Hopper), so I'm really excited to have that come to screen once again," she added.

The show's co-creators, Matt and Ross Duffer, previously addressed the bullying claims at the Los Angeles premiere.

"Obviously, you understand I can't get into personal on-set matters, but I will say we've been doing this for 10 years with this cast, and at this point they're family and we deeply care about them," Ross told THR. "So, you know, nothing matters more than just having a set where everyone feels safe and happy."

The first four episodes of the final season of Stranger Things are now streaming on Netflix.