The Sex and the City star revealed that she recently had to deal with a bout of nerves while shooting her upcoming film I Don't Know How She Does It alongside Pierce Brosnan.
Parker told Vogue: "I lose my appetite. By Wednesday of the first week on I Don't Know How She Does It, I was sobbing.
"I was apologising. I was feeling so awful and ashamed, like I had let the director down. If only they would not tell me when the camera was running, I would be okay. I'm like that two weeks into every movie."
However, Parker admitted that she felt "comforted" by Brosnan, as he experiences similar difficulties as an actor.
"He was a nervous wreck. Of course, by then I was really relaxed, but I was so comforted by it," she explained.
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Watch the trailer for I Don't Know How She Does It below: