Isabelle Fuhrman as Leena Klammer / Esther Albright

Julia Stiles as Tricia Albright

Rossif Sutherland as Allen Albright

Hiro Kanagawa as Detective Donnan

Matthew Finlan as Gunnar Albright

Samantha Walkes as Dr. Segar

David Lawrence Brown as Dr. Novotny

Lauren Cochrane as Officer Leahy

Gwendolyn Collins as Anna Troyev

Kristen Sawatzky as Federica

Jeff Strome as Lobby Guard

Andrea del Campo as Betsy

Alec Carlos as Mike

Alicia Johnston as Karen

Liam Stewart-Kanigan as Dude 1

Jade Michael as Girl 1 / Madison

Sarah Luby as Receptionist / Claire

Maxwell Nelson as Little Boy

Bradley Sawatzky as Officer Kusnetsov

Stephanie Sy as Flight Attendant

Marina Stephenson Kerr as Society 1 / Olive

Sharon Bajer as Society 2 / Gertrude

Kennedy Irwin as Esther Body Double

Sadie Lee as Esther Body Double

Erik Athavale as Orderly

Parker Bohotchuk as Laughing Partier #1

Maxine Sanders as Laughing Partier #2

Adam Hurtig as Guard (uncredited)

Morgan Easton-Fitzgerald as Young Esther (uncredited)