The Irish actor did some interesting "research" while preparing to play the kinky Christian Grey

Credit: R Chiang/Splash News Online

Proud father by day, dominant in a kink club by night. It was a tough job, but Jamie Dornan had to do it.

To prepare to play Christian Grey in the highly anticipated erotic novel adaptation Fifty Shades of Grey, Dornan told Glamour he had to leave his infant and wife home to visit the dark underbelly of the BDSM world.

“For research, one rainy Tuesday evening, I kissed the wife and baby good night and went to watch a dominant-submissive session in a dungeon,” said the Irish actor, 32.

The show was run by Fifty Shades‘ “adviser” on the sexual subculture of bondage, dominance and sadomasochism. But he wasn’t quite the punishing presence Dornan expected: “I watched him do his thing … It was quite jovial, a very different approach to how I saw Christian being in the Red Room. I think Christian takes it a bit more seriously.”

One thing Dornan himself took seriously was his costar Dakota Johnson‘s comfort while filming the infamously racy sex scenes from EL James‘s novel.

“Some of the Red Room stuff was uncomfortable,” he admits. “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.”

Johnson, 25, confirmed, “It’s stressful enough to be tied to a bed naked in a scene. But then they call cut, and you’re still tied to the bed, naked. Jamie would be the first one to throw a blanket over me.”

And, while Johnson didn’t accompany Dornan to the sex club, the on-screen couple did share a personal trainer. “I was going be naked, so I wanted to look good,” says Johnson.

She also did her own, more intimate personal preparation: “[I] had more waxing than any woman should have!”

Fifty Shades of Grey hits theaters on Feb. 13.