The British heartthrob says that although he is a huge fan of the director and had promised to do anything he asked, he drew the line at frontal nudity.
Five minutes before the filming began, the director asked Pattinson to do the racy scene but the actor found it difficult and decline.
"He took it really well. At the start, it's a very bizarre scene that you won't see again in another movie, I promise," Pattinson said.
While the 26-year-old enjoyed making the movie, based on the novel by Don DeLillo, Pattinson said he was anxious he would not be good enough for the role.
"I spent two weeks in a hotel room worrying and confusing myself," he said.