Jennifer Lawrence is basically what would happen if your dorky best friend became a world famous actress. Despite being known for her major acting chops and insane versatility in her roles, JLaw off-camera is klutzy, TMI-prone, and giggly, with a love of food and toilet humor. Although there's been a little bit of speculation over the years that she is faking or exaggerating her most endearing traits, those accusations never quite stuck. In Jennifer Lawrence's appearance on The Tonight Show, she pretty much proved once and for all that being a good actress doesn't make you a good liar.
Lawrence was there to promote X-Men: Days of Future Past and Jimmy Fallon decided to play a game of Box of Lies with her. The game involved the two sitting on either side of a partition with a window in it, then choosing boxes and opening them out of view. When they saw the object that was in the box, they had to decide whether to describe it honestly or lie to the other person about what was in it. The other person then guessed if it was a lie or not and if they got the answer right then they got a point. If they got it wrong, the opener of the box got the point.
Fallon and Lawrence's game was frequently interrupted by their own giggles and improv situations. When Fallon made the observation that the window was like looking through a mirror, he and Lawrence mimed one another's moves with the appropriately horrified expressions one would expect from such a scene in a movie. Later, they did impressions. Despite that, Lawrence still ultimately ended up losing the game because, as it turns out, she's a pretty terrible liar. Either that, or Fallon was just really, really good at seeing right through her.
Watch the game below.