Bening and Irons star in "Being Julia," (search) directed by Istvan Szabo, who made "Sunshine," the 1999 epic following three generations of a Hungarian-Jewish family.
"Being Julia" will open the festival on Sept. 9.
Based on W. Somerset Maugham's novel "Theatre," "Being Julia" is the story of a London stage star in the 1930s who grows bored with her success and stale marriage and finds new lust for life in a fling with a young American.
"Szabo has made a tremendously playful and uplifting film, capturing the effervescence of 1930s theatrical life with graceful panache," said Piers Handling, Toronto festival director, in a statement Tuesday.
The festival, a major launchpad for Hollywood's fall films and Academy Awards (search) contenders, runs through Sept. 18.