Oscar-winning actress Jennifer Lawrence may have looked stunning at the Los Angeles premiere of “The Hunger Games: Catching Fire” on Monday, but those of us who were photographing her walking the red carpet could tell that something was clearly off with our usually carefree and happy actress.

It turns out Lawrence was experiencing severe abdominal pain for weeks leading up to the LA premiere and was actually in the hospital the day of the screening due to her stomach issues. That explains why Jennifer was extremely late to the premiere and did not seem happy to be walking the red carpet.

The 23-year-old actress told USA Today: “I’m just exhausted and I was getting these stomach pains. My stomach is a little swollen, just from the way I treat it. I was supposed to be at the premiere (in Los Angeles), but I’m at the hospital.”

She also revealed that she underwent an endoscopy. Jennifer detailed the scary trip to the hospital on The Late Show with David Letterman.

“I just did this thing yesterday called an endoscopo-something, where they put you to sleep.”

Jennifer added, “I thought I had an ulcer, but it turns out it was a ‘fulcer.’ I just had this really bad pain for, like, three weeks. And you know you can only (expletive) 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.'”

Photo Credit: Emerson Boergadine for CelebMagnet