“It was crazy,” she tells PEOPLE in this week’s issue. “During the summer I do a lot of yoga, but I got a bursa on my shoulder so I had to lay off the yoga. Then I got appendicitis so I was like, ‘What the hell is happening?!’ ”
Moore, 54, says the ordeal initially landed her in the ER.
“Oh my God, I was in so much unbearable pain, I thought I was going to die,” she says.
After her appendectomy, the actress’ husband, director Bart Freundlich, snapped a few photos of her removed appendix so Moore could show friends and “everyone, whether they ask or not,” she says, laughing. “It’s really gross!”
The Hunger Games: Mockingjay, Part 2, in which Moore returns as President Alma Coin, hits theaters Friday.
For more of Moore’s One Last Thing interview, pick up PEOPLE’s Sexiest Man Alive issue, on newsstands Friday