Nighy will play a veteran M15 officer who is forced to quit his job to solve the mystery behind a file that threatens the job's stability.
Hare received a Lucille Lortel Award for Stuff Happens, Tony Award nominations for Skylight, Racing Demon and Plenty, and Oscar nominations for his screenplays for "The Reader" and "The Hours." Additional plays include The Vertical Hour, Amy’s View, The Blue Room, The Secret Rapture, The Judas Kiss and Via Dolorosa.
Nighy's stage credits include Hare's The Vertical Hour, A Map of the World and Skylight, with film work including "Notes on a Scandal" and "Love, Actually."
Weisz won an Olivier Award for A Streetcar Named Desire and an Academy Award for "The Constant Gardener." "The Constant Gardener" also featured Nighy and Fiennes, a Tony Award winner for Hamlet and Oscar nominee for "The English Patient" and "Schindler's List."
Gambon has recently appeared in Krapp's Last Tape and No Man's Land in the West End, as well as the "Harry Potter" films. Bremner's stage credits including Damascus and The God of Hell; he has appeared on screen in "You Will Meet a Tall Dark Stranger" and "Wide Open Spaces."
"Page Eight" is set to begin filming this month.