icon got her prankster co-star Noah Schnapp back in the best way.
The actress, 18, has alongside Noah since they were both children, with on the site this month.
Having known each other for years, Millie, Noah and the other main cast have formed deep friendships.
And what do friends do? They prank each other, of course.
The British actress appeared on The Tonight Show with Jimmy Fallon this week where she shared the prank that she – and pretty much the entire Stangers Things crew – played on Noah.
‘He’s the biggest prankster of them all,’ she said. ‘I too am pretty bad.’
‘We thought, as a crew, we needed to get him back.’
She revealed that, as she was preparing to leave the set, she called Noah at 4am pretending to cry and said he needed to come to say goodbye to her.
‘We had trash bins filled with water balloons all around, and we turned all the lights off at base camp,’ she said.
‘I called him, crying, “Noah I’m just so upset that you’re not here to say goodbye to me!”
‘And he said “Okay Mill, okay, I’ll be there.”‘
As Noah headed to set to say goodbye to the ‘upset’ Millie, the actress told him she had a present for him – before she and the rest of the crew pelted him with water balloons.
‘I get him in the middle of the car park, and all of us, about 20 people, raid him,’ she laughed.
‘Absolutely invade him, and it’s bad. But then he got really aggressive with it, got me on the floor, I was like “God, I’m a girl!”‘
Host Jimmy, as well as the studio audience, were in peals of laughter at Millie’s story, particularly as they played a clip of the surprise water fight that showed Noah getting attacked on all sides.
The upcoming fourth series of Stranger Things will see fans reunited with fan-favourite characters, including Eleven (Millie), Steve (Joe Keery) and Hopper ().
It was recently reported that the each new episode cost an eye-watering $30million (£24.4million) to make.
With nine new episodes in the series, that would mean that the entire season cost approximately $270m (£209m).
Excitement is on the rise for season four of Stranger Things, with eagle-eyed fans recently realising that a teaser had subtly confirmed the .
IT star Finn Wolfhard, who plays Mike, emphasised that the new episodes are going to get ‘darker’, .
With Harry Potter, as those movies went on, the darker they went,’ the 19-year-old actor told .
‘And that’s kind of where we’re at now. It’s a perfect progression in my opinion.’
