The Moonrise Kingdom and Fantastic Mr Fox filmmaker also said that frequent collaborators such as Adrien Brody, Owen Wilson and Edward Norton will also appear in the upcoming film, which he describes as a "Euro movie" and a "period picture".
He told The Hollywood Reporter: "I can tell you properly who it is. We have Ralph Fiennes, and we have Tilda Swinton and Jeff Goldblum, Willem Dafoe, we have F Murray Abraham and Jude Law, and we've got Adrien Brody, Edward Norton, Harvey Keitel, Jason Schwartzman, Bill Murray, and Mathieu Amalric."
He added: "And I think Owen is gonna have a little part, too. Oh, Saoirse Ronan has quite a big part. I'm thinking if I've forgotten anybody. Yeah, we have a good group."
Ralph and Saoirse have been confirmed as the leads in The Grand Budapest Hotel, which will be directed and written by Wes in his solo writing debut.
The film is scheduled for a 2014 release.