During the filming in Vancouver, Canada, they looked blissful as they wrapped their hands around each other's waist.
At one point, Dornan, who plays Christian Grey, was seen handing over a car key to his Johnson, seen as Anastasia Steele in the film, reported Aceshowbiz.
In the books, Christian and Grey indeed get married.
The "Fifty Shades of Grey" sequel will follow the couple as Christian wrestles with his inner demons and Anastasia must confront the anger and envy of the women, who came before her.
Directed by James Foley, it is set for a US release on February 10, 2017.