The Working Title film will depict Armstrong's struggle with testicular cancer in the '90s to his spectacular fall after it was revealed that he took performance-enhancing drugs, the Hollywood Reporter said.
If the project comes through, it would be a big opportunity for 32-year-old Foster, who has been mostly a part of multistarrers.
John Hodge, a frequent collaborator of Danny Boyle whose credits include "Shallow Grave", "Trainspotting" and the recent "Trance", is behind the script while Tim Bevan and Eric Fellner are producing.
The cyclist's life is subject of at least three films. Apart from Working Title, both Warner Bros and Paramount are developing their versions.