Bridesmaids star Chris O’ Dowd will play journalist David Walsh in the upcoming Lance Armstrong biopic, directed by Stephen Frears.

The film will be based on Walsh's book Seven Deadly Sins: My Pursuit of Lance Armstrong, which chronicles the journalist's efforts in exposing seven-time Tour de France winner Armstrong for doping in order to win races.

Walsh was one of the writers who uncovered Armstrong’s performance-enhancing substance abuse.

Ben Foster, who has starred in X-Men and Hostage, has signed on to play Lance.

Ben Foster will play disgraced cyclist Lance Armstrong

Breaking Bad star Jesse Plemons (Todd Alquist) has also been tipped for a supporting role in the film.

Cyclist Armstrong was stripped of all his medals and banned from competitive racing in 2012 following an investigation.

The film charts his rise through the 1990s and early 2000s, his battle with cancer and his dominance of pro cycling. It also follows Walsh who was at first charmed by Armstrong, but ultimately became an integral figure in exposing the doping rife within the sport.

Warner Bros. also has a film about the cyclist in the pipeline ,titled Red Blooded American. The film will be directed by Jay Roach and Bradley Cooper is heavily rumoured to play Armstrong.