Saoirse Ronan felt "very comfortable" performing sex scenes with rumoured boyfriend Jack Lowden

Speaking to Refinery29, she said: “We choreographed the whole thing so it felt like a dance.

"Jack and I are very comfortable with each other. We looked after each other.”

Saoirse says it was less "mechanical" as the focus was on her face and felt like "new territory for both of them.

She explained: “I don’t think he’d ever done anything like that before either. It was new territory for both of us.

“I know, I’d never done anything like that before.

“I’d done sex scenes but they’re so mechanical that they’re kind of easy to do. Whereas when it’s on your face like that...

“I just kept thinking about, what was it, When Harry Met Sally. But we had Wayne (McGregor, the film's choreographer) in there, which was brilliant.”

The 'Atonement' star says the sex scene was vital to the story as sexuality was "fluid" in that period in history and it was also a "very important" moment in the young Queen's life.

She said: “They lived in a time when sexuality and sex was quite a fluid thing. Sex was a separate thing from marriage.

“As a queen, though, sex was performed in order to produce an heir.

"What was so great about having that moment when Henry (Jack) goes down on her is that it’s purely for her.

“That’s a sexual revelation purely for her.

"It’s not to perform her duty, it’s not to give anything back to anyone else or to the state.

“It’s for her. It was so important to see this young girl experience this pleasure, probably for the first time, and have that be a real sort of revelation.

“It was just another element to her humanity.”

Though Saoirse and Jack are believed to have started dating on set, others working on the movie had no idea they were together until a screening of the movie in New York last week.

A source said at the time: "We don't know when they got together, we only found out on Tuesday night when they rolled up together - but they seem very happy and sweet."

After the screening, the pair looked very close at the afterparty at Tavern on the Green.

An insider observed: "Jack was following her all over. He even followed her to the bathroom and was waiting outside for her. They were very close."

Saoirse was previously believed to be dating the 'Dunkirk' actor's brother Calum, a ballet dancer, after they met at the BAFTAs earlier this year, but she has been increasingly spotted with Jack in recent months, including on a vacation to the Dominican Republic.