The duo appear opposite each other in director Francis Lee's new period drama as Mary Anning and Charlotte Murchison, as they embark on a passionate love affair during the 1840s.
On why she made sure their intimate sequence was shot on Ronan's birthday, the 45-year-old Oscar winner told Entertainment Weekly: "I just wanted her to have, frankly, a great memory in her film life, regardless of how the scene played out or the movie turned out.
"I knew that it would be [great] just because of the experience that we would share together. I knew that it would be very equal."
The two actresses chose not to rehearse and choreographed the scene themselves, while only female crew members were allowed in the room.
"I just could feel that Saoirse and I had the same ideas in terms of what we wanted to express in the scene, the emotional underpinning of the scene, the connection between these two women – which is, of course, more important than anything in any love scene," explained Winslet.
"We were on the same page in terms of that."
Ammonite is out now in UK cinemas, while US viewers can catch it from November 13.
Digital Spy has launched its first-ever digital magazine with exclusive features, interviews, and videos. Access the latest edition with a 1-month free trial, only on Apple News+.
Interested in Digital Spy's weekly newsletter? Sign up to get it sent straight to your inbox – and don't forget to join our Watch This Facebook Group for daily TV recommendations and discussions with other readers.
You Might Also Like