Natasha Henstridge as Sil

Ben Kingsley as Xavier Fitch

Michael Madsen as Preston Lennox

Marg Helgenberger as Dr. Laura Baker

Alfred Molina as Dr. Stephen Arden

Forest Whitaker as Dan Smithson, Empath

Michelle Williams as Young Sil

Jordan Lund as Aide

Herta Ware as Mrs. Morris

William Utay as Colleague

Don Fischer as Aide

Scott McKenna as Train Hobo

Virginia Morris as Mother

Jayne Luke as Snack Shop Clerk

David K. Schroeder as German Tourist

David Jensen as Conductor

Esther Scott as Female Conductor

Shirley Prestia as Victoria Roth, Ph.D.

David Selburg as Government Man

Melissa Bickerton as Fitch's Secretary

Lucy Rodriguez as Wedding Dress Saleswoman

Scott Sproule as Team Driver

Stogie Kenyatta as Cop

Gary Bullock as Motel Clerk

Susan Hauser as Lab Worker

William Bumiller as Club Bouncer

Caroline Barclay as Drunken Girl

Matthew Ashford as Guy in Club

Anthony Guidera as Robbie, Guy Picking Up Sil

Sara Lise as Screaming Woman

Whip Hubley as John Carey

Patricia Belcher as Hospital Admittance Clerk

Richard Fancy as Hospital Doctor

Leslie Ishii as Hospital Nurse

Marliese Schneider as Abducted Woman

Robert Mendelson as Homeless Man

Pamela Cook as Commercial Model

Lisa Liberati as Bathroom Bimbo

Ed Stone as Waiter

Dendrie Taylor as Marie

Kurtis Burow as Baby Boy

Dana Hee as Creature Performer

Frank Welker as Alien Sil (voice)

Justin Armao as Bystander (uncredited)

Jellybean Benítez as Club DJ (uncredited)

Greg Bronson as Special Forces (uncredited)

Jimmy Chunga as Commando (uncredited)

James Ent as Lt. Steele (uncredited)

Roman Güttinger as Doctor (uncredited)

Christopher Ivins as Soldier (uncredited)

Zak Knutson as Club Doorman (uncredited)

Coati Mundi as Conga Player (uncredited)

Jason Newell as Special Forces (uncredited)