Hilary Swank and Brenda Blethyn have been announced as the lead roles in Mary and Martha, a new one-off film for BBC1 written by Richard Curtis.
The drama is due be shown on BBC1 in the run-up to Red Nose Day next year.
Mary and Martha, made by Working Title Television for BBC1, follows the story of two women who both lose sons to malaria and join together to raise awareness of the disease.
Swank, playing Mary, said she was looking forward to working on “this extraordinary story”, which is directed by Phillip Noyce and will also star Lux Hanley Jardine and Sam Clafin as the women’s sons
Blethyn described the script, which was influenced by the writer’s work with comic relief, as “Curtis at his best”.
BBC1 controller Danny Cohen said the production features “a world-class mix of talent”.
Filming began this week and is taking place in America and South Africa.