The Toronto Globe & Mail noted the decision breaks with the tradition of opening the festival with a Canadian film. Amiel is British.
The world premiere of the movie, which co-stars real-life married couple Paul Bettany and Jennifer Connelly as Charles and Emma Darwin, coincides with the 200th anniversary of the birth of the noted scientist and author.
"The tension between faith and reason is prominent in contemporary culture and this intimate look at Darwin puts a human face on a man whose theory remains controversial to this day," the newspaper quoted Piers Handling, the festival's director and chief executive officer, as saying.
Also slated to screen at the festival in September are Steven Soderbergh's thriller "Informant," starring Matt Damon; Jane Campion's literary love story "Bright Star;" and Ricky Gervais' comedy "The Invention of Lying."