Foster was born in Edmonton, Alberta, Canada. She began her career at the age of 13 in a stage adaptation of James Barrie's What Every Woman Knows. In London in 1951, she appeared on stage in Agatha Christie's The Hollow and Orson Welles's Othello.
At 14 she began a radio career, subsequently moved to Toronto, and became one of Canada's top radio stars, working with Andrew Allan, drama supervisor for the Canadian Broadcasting Corporation on productions such as Stage '49. She appeared on Radio Luxembourg in a broadcast of The Lives of Harry Lime. She married Andrew Allan in 1951.

свернуть