Charles Laughton as Tiberius Claudius (archive footage)

Robert Graves as Interviewee [original author]

Josef von Sternberg as Interviewee [director] / Himself (archive footage)

Merle Oberon as Interviewee / Messalina (archive footage)

Flora Robson as Interviewee / Livia (archive footage)

Emlyn Williams as Interviewee / Caligula (archive footage)

Eileen Corbett as Interviewee [script girl]

John Armstrong as Interviewee [costume designer]

Dirk Bogarde as Narrator

John Abbott as Himself – Ms. Robson's Host (uncredited)

Robert Newton as Cassius, Captain of Caligula's guard (archive footage; uncredited)

Basil Gill as Xenophon, Claudius' doctor (archive footage; uncredited)