Knightley will play the wife of 28-year-old billionaire Eric Packer, now to be played by Twilight star Robert Pattinson.
Paul Giametti has not been listed in the official cast, despite being in talks for a role. He was expected to play one of the antagonists.
Don DeLillo's 2003 novel follows a day in the life of Packer as he meanders across Manhattan in his stretch limo, pausing to cheat on his wife, outwit stalkers and bet his client's money away.
Though Farrell and Cottilard made for a believably age-matched couple (they are 34 and 35 respectively), the casting of 24 year-old Pattinson affected the plausibility of the Packer's marriage.
Knightley - who is 25 - seems a good choice for balancing out the age gap. The wisdom of combining Pattinson and Knightley into one super sulky, pouty power couple remains to be seen...
Knightley must have made a good impression on Cronenberg whilst filming A Dangerous Method . We'll be seeing her play a troubled psychiatric patient to Viggo Mortensen's Sigmund Freud later this year.
Cronenberg recently finished the Cosmpolis screenplay and will begin shooting in Toronoto this May.
