Jamie Dornan and Dakota Johnson On Infamous 'Red Room' in 'Fifty Shades of Grey'

Dornan did things to Johnson, "I’d never choose to do to a woman."

"I didn’t hear anything until they cast Charlie," Dornan said. "I thought it was kind of funny to say that I’d auditioned to play Christian and failed miserably. Then whatever happened with [Charlie] happened, and the doors opened again."

To play Grey, Dornan, 32, said he hit the gym hard, but not too hard.

"It wasn't six hours a day. You don’t want to turn to your heavily pregnant wife and say, 'I’m going to the gym for six hours. Text me if you go into labor,'" he joked about his wife Amelia Warner, who gave birth in November.

Johnson, 25, added, "Jamie and I actually shared a trainer. It was important to me that Ana’s body look like that of an active college student. And I was going be naked, so I wanted to look good. I did a lot of working out and had more waxing than any woman should have!"

Dornan admitted that some of the scenes in that room were uncomfortable.

"There were times when Dakota was not wearing much, and I had to do stuff to her that I’d never choose to do to a woman," he said.

Johnson said Dornan was always a gentleman and the actor, added, "I felt very protective and aware that it probably wasn’t easy for her to be put in those situations, and exposed."