Kelvin Harrison Jr. has joined the cast of 'The Trial of the Chicago 7'.

The 'It Comes at Night' star joins a stellar line-up of talent that includes Joseph Gordon-Levitt, Eddie Redmayne, Sacha Baron Cohen, Frank Langella, Mark Rylance and Yahya Abdul-Mateen II in Aaron Sorkin's film.

The movie is about the infamous 1969 trial of seven men charged by the federal government with conspiracy and inciting a riot, a result of the counterculture protests in Chicago at the 1968 Democratic National Convention.

The identity of Kelvin's character is yet to be confirmed, but Yahya will play Black Panther Party co-founder Bobby Seale, whilst 'Borat' star Sacha portrays political activist Abbot Hoffman.

Kelvin, 25, has an impressive filmography which includes 'The Wolf Hour', 'Gully', 'Waves' and horror film 'It Comes at Night'.

'The Trial of the Chicago 7' has been long in the making and was due to shoot in 2018 but it had to be put on hold because Aaron had chosen to concentrate on his Broadway production of 'To Kill a Mockingbird'.

The 58-year-old filmmaker will write and direct the film, which is being produced by Steven Spielberg's Amblin Entertainment.

The 'Jaws' director considered overseeing the movie himself back in 2008, but it was delayed due to a writer's strike and then he didn't have the time to take the project on.

The legendary filmmaker tried to get the project off the ground again in 2013, with Paul Greengrass directing but his plans were scuppered because of budget issues.

Aaron was eventually approached after he had directed 'Molly's Game' in 2017.

In a statement when the film was confirmed, Aaron said: ''I'm thrilled to be making a movie about one of one of the craziest, funniest, most intense, most tragic and most triumphant trials in American history. C-7 may take place in the late '60s, but there's no better time to tell this story than today.''