* Robert Taylor as Marcus Vinicius
* Deborah Kerr as Lygia
* Peter Ustinov as Nero
* Leo Genn as Petronius
* Patricia Laffan as Poppaea Sabina
* Emlyn Williams as Chilon
* Abraham Sofaer as Ursus
* Marina Berti as Eunice
* Nigel Stock as Tigellinus
* James Robertson Justice as Aulus Plautius
This is not an exhaustive list, but it includes some of the most prominent roles.