Jamie Dornan on 'Fifty Shades of Grey' role: 'I learned all sorts of tricks'

When Fifty Shades of Grey opens Valentine's Day weekend, fans of the erotic bestseller- will see Jamie Dornan's "sex face" splashed across the big screen. The 32-year-old actor is terrified.

"It's the worst thing imaginable," Jamie tells Variety. "For all the reasons anyone would think, most people would like to keep their sex face private. The idea of a million people seeing that! I hope it happens quite fast."

Jamie and wife Amelia Warner at the 2014 GQ Men of the Year awards in London

Jamie, the Belfast-born father of a 2-year-old daughter with actress-wife Amelia Warner, accepted the role of charismatic mogul and S&M connoisseur Christian Grey after Sons of Anarchy star Charlie Hunnam dropped out in late 2013. (Dakota Johnson plays virginal college grad Anastasia Steele, the object of Christian's lust.)

He didn't go totally nude for the R-rated part.

"They were privy to everything, just not my manhood," says Jamie. "It's like one of those little satchels that Robin Hood or someone of that era would have tied on his belt. There's no back. It's tiny. I mean, it's not tiny! Because it's got to hold a lot."

Jamie, who played a serial killer in the BBC crime drama The Fall, prepped for Fifty Shades by watching The Thomas Crown Affair and American Psycho, but he wasn't quite ready for how to crack a whip and other sadomasochistic techniques.

With Dakota Johnson at the 2015 Golden Globes

"We had an adviser in the field that we'd talk to, a guy on the kink scene," he recalls to Variety. "He's a guru, and a dominant. We had some good chats with him. And then there was the practical side of things. How do you use this? I've never held that! I learned all sorts of tricks that will support me through my life."

As for the whip, "I wasn't talented at it. But I got there in the end. It's really like fly fishing."

Jamie counts among his good buddies the British actors Eddie Redmayne, now an Oscar nominee for The Theory of Everything, and Andrew Garfield, the latest Spider-man.

"We ended up staying in the canyons, renting a place together and helping each other on auditions," he says. "We've been at it a while. It's wonderful when people who you've seen give it the rigor manage to get that moment."

Perfecting the "Fifty Shades" blue-steel stare

He's also friendly with fellow Brit Robert Pattinson, of Twilight fame, who knows a thing or two about breaking into the big time — and making female fans faint in the process.

"I've been around Rob around enough. I've seen what it's been like for him," reveals Jamie, adding: "I don't remember what we talked about the last time I saw him. I think we just got drunk."