Robert Pattinson and Kristen Stewart are in a relationship, "Twilight" director Catherine Hardwicke has confirmed.

Despite previously denying they are a couple, the director – who helmed the first movie in ‘The Twilight Saga’, in which the pair play lovers – insists persistent rumors they are enjoying an off-screen romance are true.

Recalling a conversation she had with 19-year-old Kristen, Catherine told Time magazine: "I didn't have a camera in the hotel room. I cannot say. In terms of what Kristen told me directly, it didn't happen on the first movie. Nothing crossed the line while on the first film.

"I think it took a long time for Kristen to realize, ‘OK, I've got to give this a go and really try to be with this person.’ "

Catherine also admitted she initially warned Robert, now 23, about trying to pursue a romance with his co-star after realizing the British actor – who plays vampire Edward Cullen in the franchise – was attracted to Kristen.

She added: "After I cast him, I told Robert, don't even think about having a romance with her . . . She's under 18. You will be arrested."

However, Catherine – who worked on the first ‘Twilight’ film – did not direct on sequels ‘New Moon’ or ‘Eclipse’, so there is doubt over how much insight into their relationship she would have.

The 'Twilight' obsession is ripping Kristen Stewart and Robert Pattinson apart