Los Angeles, May 27 (IANS): Actors Holt McCallany and Julianne Nicholson are the newest additions to the cast of 'Amateur', the CIA thriller that Rami Malek is leading for 20th Century Studios.

The actors join an ensemble that will also include Rachel Brosnahan, Caitriona Balfe, Laurence Fishburne and Adrian Martinez, as previously announced, reports Deadline.

Based on a novel by Robert Littell, Amateur tells the story of Charles Heller (Malek), a CIA cryptographer who, after his wife is tragically killed in a London terrorist attack, demands his bosses go after them. When it becomes clear they won't act due to conflicting internal priorities, he blackmails the agency into training him and letting him go after them himself.

The film to be directed by Slow Horsesa James Hawes had its screenplay adapted by Ken Nolan, with Scott Frank and Gary Spinelli handling revisions.

Sources told Deadline that McCallany will play CIA Deputy Director Moore, a "kill whoever we want" kind of guy who has spent his career behind a desk, details as to Nicholson's role haven't been disclosed.

Hutch Parker and Dan Wilson are producing, with Malek serving as the film's executive producer.