Credit: Michael Rozman/Warner Bros.

Jessica Simpson's due date is still more than a month away, but the 31-year-old was worried she might be going into premature labor.

"I had contractions last night and I freaked out a little bit. You know those Braxton Hicks things," Simpson said on The Ellen DeGeneres Show Tuesday. "It's like these contractions that pregnant woman have towards the end. It prepares your body for delivery. I'm prepared. It's scary. It's like, 'Oh God, this can happen right now.'"

Simpson admitted that she's nervous about giving birth. "It will hurt very badly," she predicts.

The Fashion Star mentor and fiance Eric Johnson, 32, have already named their daughter, "but we're not really saying it [publicly] until the baby is here."

"We've been calling her by name. She reacts to it," Simpson told host Ellen DeGeneres, 54. "I could be one of those psycho moms that just thinks one little kick is her really listing to me. She's really like, 'Shut up!'"

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