Cdr. John Koenig

Martin Landau

Dr. Helena Russell

Barbara Bain

Maya

Catherine Schell

Alan Carter

Nick Tate

First Off. Tony Verdeschi

Tony Anholt

Guest Star

Stuart Damon

Elizia

Hildegard Neil

Dr. Charles Logan

Freddie Jones

Patrick Osgood

James Laurenson

Dave Reilly

Patrick Mower

Guest Star

Patrick Westwood

Sandra Benes

Zienia Merton

Taybor

Willoughby Goddard

Michelle Osgood

Pamela Stephenson

Carla

Isla Blair

Alien Strong

David Jackson

Magus

Guy Rolfe

Pasc

John Standing

Yasko

Yasuko Nagazumi

Interrogator

Dora Reisser

Captain Michael

Bernard Cribbins

Shermeen Williams

Lynne Frederick

Humanoid

Bernard Kay

Etrec

Michael Gallagher

Sares/Controller

Cassandra Harris

Dr. Ben Vincent

Jeffery Kissoon

Vindrus

Stuart Wilson

Cantar

Peter Duncan

Mentor

Brian Blessed

Alien Transporter

Godfrey James

Zamara

Billie Whitelaw

Annette Fraser

Anouska Hempel

Zarl

Leigh Lawson

Jelto

Angus MacInnes

Bill Fraser

John Hugginson

Maya/Creature

Albin Pahernik

Zova

Stacy Dorning

Alien Invisible

Roy Marsden

Lyra/Maurna

Veronica Lang

Security Lieutenant

Marc Zuber

Derek Wadsworth

Mirella

Margaret Inglis

Eddie Collins

Nicholas Campbell

Johnson

John Alkin

Bill Fraser

John Hug

Brian/Robot

Michael Sharvell-Martin

Number Eight

Geoffrey Bayldon

Stal

Anthony Blackett

Chris Potter

Brian Osborne

Lew Picard

Gerard Paquis

Terence Feely

Carson

Anthony Forrest

Old Lady

Peggy Ledger

Roy Baker

Dr. Raul Nunez

Raul Newey

Dr. Mathias

Anton Phillips

Fred Freiberger

F. Sherwin Green

Peter Pennell

David Kano

Clifton Jones

Paul Morrow

Prentis Hancock

Victor Bergman

Barry Morse