Rockwell boards Swank's 'Betty Anne'

Rex Features

Sam Rockwell has joined the cast of Hilary Swank's legal drama Betty Anne Waters, says The Hollywood Reporter.

The film, based on a true story, centres on an unemployed single mother who spends ten years earning a law degree to prove that her jailed brother is innocent of murder.

Minnie Driver is also among the cast as a law student with a chequered past. Tony Goldwyn will direct from a script by Richard LaGravenese and Pamela Gray.

Frost/Nixon star Rockwell recently signed up to play villain Justin Hammer in Iron Man 2.