The Northern Irish actor plays Christian Grey, the mysterious billionaire with a penchant for raunchy sex, while Dakota is his naïve lover Anastasia Steele.
Fifty Shades is jampacked with sexy scenes and sensual sequences – some of which we saw previewed in this week's trailer release.
Speaking on Today, Jamie said: "[Chemistry] is a big part of it. And having trust. We got ourselves into situations that don't feel natural and aren't that easy and you need to have the trust there."
Dakota added: "It's not like a romantic situation. It's more technical and choreographed. It's more of a task."
Poor Jamie! We wonder how many other women would find it a task...
On the show, Jamie also revealed how he celebrated his Fifty Shades of Grey role in the least Christian Grey way possible… going straight to sleep!
The handsome actor found out he'd been chosen to play the enigmatic billionaire with a racy sex life via a late night phone call.
A call that was so late all he wanted to do was sleep.
"I was in London at the time when it finally happened," he said. "It was two in the morning and I was waiting for the call, so when it finally came, I was asleep pretty soon after I found out.
"I wasn't in a normal timezone where I could g and party. My heavily pregnant wife was downstairs sleeping so I joined her in bed and went to sleep."
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Watch the trailer in full here: