While one half of YouTube pranksters Smosh thought he was calling the shots and pulling the wool over Jen's eyes, his buddy had actually let Jennifer in on the secret and she was playing along!
And what follows is brilliant!
While the YouTube prankster is fed lines through his earpiece by his Smosh co-star behind the scenes, Jen plays along, acting exasperated, keeping a straight face and genuinely being fantastic.
Jennifer's Hunger Games co-stars Liam Hemsworth and Josh Hutcherson, meanwhile, are feeding lines to Jennifer. It all sounds complicated but watch the video and it's all so clear. (And funny!)
After Jennifer storms away, her protective co-stars come rushing in to confront the prankster and ask what exactly happened. "It wasn't funny, man," said Josh. "Jen is usually pretty cool with that kind of thing…"
And then the ball drops!
Jen comes in with the young fan who masterminded the entire prank and it's hugs all around!
You can catch Jen, Liam and Josh in The Hunger Games: Mockingjay Part 2, which arrives in cinemas on 20 November.
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