Ralph Fiennes, Colin Firth, Gary Oldman and Michael Fassbender are joining Tinker, Tailor, Soldier, Spy for Working Title and Studio Canal. 

Variety reports that Tomas Alfredson (Let the Right One In) has already signed on to direct and will begin shooting in October in London. In other Working Title news, Screendaily reports that the studio will reteam with Joe Wright for a live-action feature adaptation of Hans Christian Andersen's fairytale The Little Mermaid.

Based on John Le Carre's 1974 bestseller, Tinker, Tailor is set in the aftermath of the Cold War and involves a spy hunt within the highest echelons of the British Secret Intelligence Service. Peter Morgan wrote the adaptation.

Tim Bevan and Eric Fellner are producing. Debra Hayward, Liza Chasin, Le Carre and Morgan are exec producing.

Meanwhile, Abi Morgan has written the Little Mermaid adaptation, which was inspired by a children's puppet theater production of the classic at London's Little Angel Theatre Company.

Wright previously worked with Working Title on his first three features: Pride & Prejudice, Atonement and The Soloist.

Story: http://www.hollywoodwiretap.com/?module=news&action=story&id=49759