According to a recent interview, Brie Larson filmed some of her part of Avengers: Endgame without even realising that was what she was doing.
If there is one thing we've learned in the build up to Avengers: Endgame, it's that nobody really knew the whole thing until they saw it on the screen.
The script, storyline, and plot have been kept closely guarded so as not to fall onto the internet, or into the wrong hands.
However, you'd imagine that level of secrecy wouldn't entirely have to apply to the actors who were in the bloody thing. Well, you'd be wrong.
Appearing on The Tonight Show Starring Jimmy Fallon, Larson explained that she filmed a tag for the upcoming film whilst filming a green screen shot for Captain Marvel.
However, she explained that everything was so secretive that she had absolutely no idea what was going on.
Larson told Fallon: "There's a tag in Captain Marvel where it like whip pans to me and all the Avengers and I'm like 'where's Fury?' I didn't know that was a tag for Captain Marvel.
"I didn't know what that was that we were shooting. There was also nobody else there. I was by myself on a green screen and I walked in and they were like 'just real quick we're going to whip pan over to you and you're gonna go 'where's Fury' and I was like 'cool cool, got it got it, got it'.
"They whip-pan over to me and I was like 'wait, where...where is he actually, like...is he in the room...like what room am I in? Is he in the other room? Like another universe?'."
Larson as Captain Marvel. Credit: Marvel
She continued: "They're like 'he's very gone', and I was like 'I think that this means he's like...he's dead.
"So then afterwards they were like 'okay great, so after you say that could you look over to the other people in the room?' and I was like 'okay...who else is in the room?', and they were like 'five people' and I was like 'okay, could I have a tape mark' and they were like 'sure'.
"So they put the tape marks up and I went 'where's Fury' and just kind of..."
Then she looked around the studio, addressing a load of imaginary Avengers, basically.
It was only once the film came out that she realised what had gone on.
Brie Larson. Credit: PA
She added: "And then I had the pleasure at the Captain Marvel premiere and seeing what the scene was and going 'oh, that's what that meant'."
Hopefully you now understand what it's all about. If you don't yet, Avengers: Endgame hits screens in the UK today - 25 April - and tomorrow in the United States.
Featured Image Credit: PA