And, while we're sure all eyes were glued on the ridiculously good-looking Jamie, Dakota kind of stole the show in her stunning plunging gown.
The 25-year-old actress wowed the crowds in a white Saint Laurent dress, which was delicately enhanced with silver embellishment around the drop bustline and waist.
Dakota paired her frock with Sidney Garber jewels and a Roger Vivier clutch, and finished with a plum lip for a pop of colour.
In the film - which lands in cinemas today - Dornan plays Christian Grey, a billionaire businessman who seduces student Anastasia Steel (Dakota) into a steamy S&M relationship.
Based on the 'mummy porn' book of the same title by E.L James, the movie hits the big screen just in time for Valentine's Day.
But there's one couple who won't be watching it together, and that's the leading man and his real-life wife, Amelia Warner.
Speaking to the Daily Telegraph, Jamie said of Amelia, "She hasn't seen the film and I don't think she will, to be honest. I'd understand if she didn't want to."
He also said there could be a few embarrassing moments for his other loved ones, adding, "I think there's some stuff where my family and friends will never have seen that side of me before, but it wasn't enough to make me not want to do it."
Jamie and Dakota also posed for pics with the film's director, Sam Taylor-Johnson, and the book's author, E.L James during last night's star-studded premiere.
We're still swooning over that dress (and Jamie, of course...)
LOVE JAMIE? This gallery is just for you. You can thank us later...
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more