Harriet Tubman is finally getting the movie treatment, but not for the big screen. Viola Davis will play the abolitionist for a HBO biopic that will be written by John Adams writer Kirk Ellis. Steven Spielberg’s Amblin TV will be producing with HBO Films.

The script is based on Bound for the Promised Land by Kate Clifford Larson, reports Deadline. Tubman was born a slave, but escaped and organized the Underground Railroad, leading over 300 slaves to freedom in the North.

The Hollywood Reporter also confirmed the casting. It’s not clear when the film will air.

Ellis has a long history with HBO. Aside from John Adams, he has also worked on the upcoming All The Way with Bryan Cranston.

Davis has Oscar nominations for her performances in Doubt and The Help. She just starred in ABC’s How To Get Away With Murder, which earned her a SAG Award in January.

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