Russell Crowe will play the lead role in "State of Play," the political thriller co-starring Helen Mirren, Edward Norton, Robin Wright Penn and Jason Bateman.
Pitt, 43, who dropped out of the film last month, had wanted to make the movie but was not pleased with the script, according to Hollywood trade paper Variety.
Crowe, 43, will play a former political consultant who is now a journalist investigating a murder linked to a congressman whose campaign he once ran.
Directed by Kevin Macdonald ("The Last King of Scotland"), "State of Play" begins filming this month.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969