Margot Robbie was worried about filming Wuthering Heights so soon after giving birth.

The Barbie actress was grateful for reassurance from director Emerald Fennell as she took on the role of Cathy in the new movie adaptation of Emily Bronte's novel because she wasn't in her usual "headspace" after welcoming her son with husband Tom Ackerley last year.

Margot told British Vogue: "I was three months postpartum when we started shooting. So I was in a very different headspace. I didn't do my usual routine. It was more haphazard...

"And I remember saying to Emerald, 'What if I'm not prepared enough?' She kept saying, 'I don't want you to prepare. I just need you to be in the moment.'

"Which was a lovely way of relieving my anxiety. It was about being in my body as opposed to my head."

Speculation about the movie's raunchiness mounted after the trailer hinted at steamy moments between Margot and co-star Jacob Elordi but Margot claims that audiences will be "surprised" at the picture's content when it is released in February.

The 35-year-old star said: "Everyone's expecting this to be very, very raunchy. I think people will be surprised...

"Not to say there aren't sexual elements and that it's not provocative - it definitely is provocative - but it's more romantic than provocative. This is a big epic romance."

Margot believes that Wuthering Heights will fill a gap in the romantic movie genre.

The A Big Bold Beautiful Journey star said: "It's just been so long since we've had one - maybe The Notebook, also The English Patient. You have to go back decades...

"It's that feeling when your chest swells or it's like someone's punched you in the guts and the air leaves your body. That's a signature of Emerald's. Whether it's titillating or repulsion, her superpower is eliciting a physical response."

Robbie explained that some of her scenes with Elordi's Heathcliff left her feeling "weak at the knees".

The Australian actress said: "It almost made me feel weak at the knees. It was the little things that we loved as two women in our 30s, and this movie is primarily for people in our demographic. These epic romances and period pieces aren't often made by women."