The actress told Jimmy Fallon Tuesday on "The Tonight Show" she was in such a dark place during production of the Darren Aronofsky thriller that she needed the comedic relief of E!'s biggest reality TV franchise to keep her grounded.
"I got to such a low point in the film emotionally that eventually I had to bring the Kardashians in," she said. "Not in person, obviously."
"I've never done something that horrifying so I started getting scared a couple days before and I was like, 'I need a tent to be away from all of the extras, because I didn't know what I would do, and then eventually one Kardashian came and then another Kardashian came, but it was just a computer that was playing the 'Kardashians' with their headshots and it also had little notes to me, from them, that I had written."
J-Law later said she is wary about sharing those humorous notes since she doesn't want to offend anyone, although it did help her cope with those dark days.
She went on to say the new movie is so dark and challenging to viewers, that she's actually worried about her family seeing it. But both she and Fallon agreed they don't know how to explain to people why without possibly spoiling it.
"I don't know what to tell people, either. I've gone between not saying anything and telling people everything," she said. "You can Google all the times I've just spilled the entire plot."
When Fallon began to set up the premiere of the movie -- a writer who takes his wife into a house in the middle of nowhere, Lawrence blurted out, "It represents Earth!"
What else do we know? "A stranger comes to the door, Ed Harris, it just gets weird. It gets insane," Fallon said.
Then they busted out singing "Santa Claus Is Coming to Town."
When the pair was done debating what spoilers they could drop and singing impromptu Christmas carols, they hurled axes at a target. Watch that video below.