Jacob Tremblay has joined the cast of Xavier Dolan’s drama “The Death and Life of John F. Donovan” with shooting underway in Montreal.

Seville International is selling to international markets at the Berlin Film Festival. Tremblay will star alongside Kit Harington, Jessica Chastain, Natalie Portman, Susan Sarandon and Kathy Bates.

Principal photography will continue in Prague, the U.K. and New York. “John F. Donovan” stars Harrington an American TV star in his late twenties and his correspondence with a young actor-to-be, played by Tremblay, who is living with his mother (Portman) in England. Their lives take dramatic turns when the existence of their pen pal relationship is publicly exposed, sending Donovan in a downfall.

“The talent involved in this project is unparalleled,” said Anick Poirier of Seville International.  “Xavier is a visionary and he has proven once again that he attracts first class actors by adding Tremblay to this superb ensemble.”

Producers are Lyse Lafontaine of Lyla Films and Xavier Dolan and Nancy Grant of Sons of Manual along with executive producer Joe Iacono.

Tremblay broke through in “Room” opposite Brie Larson and will next be seen opposite Naomi Watts in Colin Trevorrow’s “Book of Henry” for Sidney Kimmel, Double Nickle and Focus Features and Lionsgate’s “Wonder” with Julia Roberts. He is also set to star in Shane Black’s “Predator” for Davis Entertainment and  Fox.

Tremblay is represented by UTA, Play Management and Jackoway Tyerman.

Seville International is handling international sales of the film in all media around the world, with the exception of France where the producers and Seville International jointly sold the rights to Mars Films, and in the U.S., where the film is being jointly handled by CAA.