Dakota Johnson had "preconceived notions" about Justin Timberlake before co-starring in 'The Social Network'.

The 34-year-old actress and the 43-year-old singer worked together on David Fincher's 2010 movie in which he played Napstar founder Sean Parker and she portrayed college student Amelia Ritter, who had a one-night stand with him after meeting at a bar.

When asked if she had any preconceived ideas about Justin before filming, Dakota told Vanity Fair: "Are you kidding? I was just like 19 and straddling Justin Timberlake and like whipping him in the face with my hair. 100 per cent had preconceived notions, but he was lovely and kind and really welcoming for a person that was just a stranger.

"I think that because this was 'The Social Network’ and David Fincher, we did this so many times that I’m like, I’m in it. I know it, I know all the lines. It’s still there.

“We did it so many times that I feel like I remember this and it’s happening now. Maybe I was traumatised."

Justin's treatment of Dakota was vastly different to that of the movie's star Jessie Eisenberg, who played Facebook co-founder Mark Zuckerberg.

She previously told co-star Andrew Garfield in a joint interview with Vanity Fair: "You and Jesse were so busy on that movie, and I was obviously in it for four seconds, but I spent a few days on set just watching. I remember sitting down with you guys when you were having lunch one day, and you asked me loads of questions.

"You were really nice — and Jesse didn't acknowledge me. He was probably in character."