Director Lee Daniels got worried and even offered to stop filming after fearing she had been hurt during the graphic action. But the 45-year-old insisted they carry on - although she needed make-up the next day to cover her bruises.
Co-star John Cusack - who played a prisoner on death row - revealed that some shots were too explicit for harrowing drama "The Paperboy".
"There's a lot more s*** in there that was cut out, believe me. I was afraid I was hurting her, but she was more fearless than me," thesun.co.uk quoted Cusack as saying.
"We shot the rough sex scene on day one, and I barely knew her. Next day, Nic showed up with bruises all over her legs," he added.
The film released last year.