The U.K. premiere of “Ammonite,” starring Kate Winslet and Saoirse Ronan, and directed by Francis Lee (“God’s Own Country”), will close the British Film Institute London Film Festival on Oct. 17.

Set in the 1840s, the film follows self-taught paleontologist (Winslet) who is entrusted with the care of a young, married woman (Ronan), who recovering from a personal tragedy. They begin an all-consuming love affair that will defy all social norms and alter the course of both lives irrevocably.

Festival director Tricia Tuttle said: “Francis has the ability to place love stories of breath-taking intimacy within a rich socio-political context, always with a delicate touch, and here offers reflections on class difference and the erasure of women from scientific history. In Saoirse Ronan and Kate Winslet, ‘Ammonite’ features two enthralling and gifted leads; Kate in particular, who appears in almost every scene, gives a fearless and complex performance.”

The film, which will bow at the Toronto Film Festival in September, is co-financed by the BFI and BBC Films. See-Saw Films developed the film with the BFI and BBC Films. It is produced by Iain Canning, Emile Sherman and Fodhla Cronin O’Reilly. “Ammonite” will be released in U.K. cinemas in 2021.

It is one of 13 films from the program that will screen in previews across the U.K. The festival this year will follow a hybrid online-physical model. As previously announced, Steve McQueen’s “Mangrove” will open the festival.

The 64th BFI London Film Festival takes place Oct. 7-18.