Philip Seymour Hoffman (Robert Gelbart (Violin))
Christopher Walken (Peter Mitchell (Cello))
Catherine Keener (Juliette Gelbart (Viola))
Mark Ivanir (Daniel Lerner (Violin))
Imogen Poots (Alexandra Gelbart (Violin))
Madhur Jaffrey (Dr. Nadir)
Liraz Charhi (Pilar)
Wallace Shawn (Gideon Rosen)
Anne Sofie Von Otter (Miriam Mitchell)
Pamela Quinn (Parkinson's Class Instructor)
Brooklyn Parkinson Group (Parkinson's Class Participants)
Cristian Puig (Flamenco Guitarist)
Rebecca Tomas (Flamenco Dancer)
Megan McQuillan (Sotheby's Executive)
David Redden (Auctioneer)
Ted Hartley (Winning Bidder)
Stephen Payne (Jack)
Alyssa Lewis (Little Girl in Subway)
Attacca String Quartet (Julliard Student Quartet)
Keiko Tokunaga (Violinist)
Luke Fleming (Violist)
Andrew Yee (Steve the Cellist)
Amy Schroeder (Julliard Classroom Student)
Nina Lee (Herself)