Chris O'Dowd has been confirmed as a cast member for the upcoming Lance Armstrong biopic.

The Roscommon actor will play journalist David Walsh who was one of the key figures who pursued the disgraced cyclist over his use of performance-enhancing drugs.

The film will be based on Walsh's book Seven Deadly Sins: My Pursuit of Lance Armstrong which chronicles that hunt for the truth.

Ben Foster who has starred in X-Men: The Last Stand and Contraband will play Armstrong.

Breaking Bad actor Jesse Plemons and French star Guillaume Canet have supporting roles.