Jennifer Lawrence Talks About Her 'Fulcer,' Being Cold on 'Letterman' (Video)

Jeffrey R. Staab/CBS
Jennifer Lawrence on Wednesday's "Late Show"

The actress describes her trip to the emergency room that led her to reschedule promotional appearances for "The Hunger Games: Catching Fire."

Jennifer Lawrence is in the midst of a massive worldwide publicity tour for The Hunger Games: Catching Fire, on top of filming the next two installments in the franchise and working on other films like David O. Russell's American Hustle.

So, it wouldn't be surprising if she was a bit under the weather. On Wednesday, she had to reschedule a number of talk show appearances, including interviews on Good Morning America, and The Daily Show and told David Letterman her health scare sent her to the emergency room.

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She thought she had an ulcer, which she doesn't, but she still doesn't know what's wrong with her.

"I thought I had an ulcer and it turns out it was a 'fulcer,' " she explained on Wednesday's Late Show, inventing a term for a fake ulcer. "I just had this really bad pain for like three weeks, and you can only shit your pants so many times a day before you have to go to the emergency room, before you're like 'I need to go to the hospital.' "

Lawrence then revealed she had an endoscopy and described freaking out as she went under the anesthesia and her bizarre experience after she woke up and the anesthesiologist asked her if she had any dreams.

"I was like, 'I dreamed there was a nuclear bomb went off' and then the first like lucid conversation I remember having was about the Kardashians," she said. "Then I put my hand on the anesthesiologist's chest and I said 'Would you just please promise me something? Will you promise me you'll watch Real Housewives of Beverly Hills, please?' "

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So if she doesn't have an ulcer, what's wrong with her?

"They said that the problem is either in my lower intestine or my mind," she recalled.

She realized she wasn't in pain at the moment, leading her to say "I might actually be crazy, as many jokes as I make."

But she's determined to get to the bottom of this.

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"Something's wrong with me, and I'm going to find out what it is," she added, her voice rising with mock intensity. "I don't care how many medical bills I rack up, I'm going to get a disease. Somebody's just going to have to give me something so I'm like, 'OK, that's what I have.' "

Letterman later asked if she's always been a hypochondriac, to which Lawrence responded, "I don't know what that means but it sounds like a disease, which means I have it."

One thing she was definitely suffering from in the notoriously frigid Ed Sullivan Theater was being too cold.

Lawrence complained she was shivering, saying it felt like all the windows were open, so one of Letterman's staffers gave her a bright pink comforter that she wrapped herself in for the rest of the interview.

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At one point, Letterman got under the covers with her, pulling it above both of their heads and pretending that the audience could no longer see them.

"Oh, I wish they'd go away, don't you? Go away everyone," Letterman said.

Lawrence probably would have liked some privacy to get some rest, repeatedly noting during the interview that she's quite tired from filming and promoting the Hunger Games movies.

When Letterman asked how many movies in the series they were going to do, she said, "We're going to make them like the Now [That's What I Call Music ] albums, get all the way up to 47, 48: We're even hungrier. Or the last one: We're finally full."

Watch clips of Lawrence's appearance on the Late Show below.