Four extraterrestrials, X-1, X-2, X-3 and X-4, arrive on Earth in the early sixties. Here they decide to take on human features to study the terrestrials incognito, but end up getting involved in the Roman "dolce vita".
Paolo Panelli
Carlo Croccolo
Enzo Garinei
Alfredo Landa
Magali Noël
Ciccio Ingrassia
Franco Franchi
Pietro De Vico
Valeria Fabrizi
Nando Martellini
Umberto D'Orsi
Riccardo Billi
Francesco Mulè
Lando Buzzanca
Mario De Simone
Margaret Lee
Tullio Altamura
Nerio Bernardi
Dominique Boschero
Alicia Brandet
José Calvo
Eva Darin
Thea Fleming
Agata Flori
Jenny Folchi
Corinne Fontaine
Cristina Gaïoni
Aldo Giuffrè
Annie Gorassini
Margaret Rose Keil
Salvo Libassi
Rosemarie Lindt
Mimmo Poli
Lucia Modugno
Bruno Scipioni
Seyna Seyn
Alfredo Tasso
José María Tasso
Elena María Tejeiro
Ángel Ter
Pietro Tordi
Renato Turi
Max Turilli
Raimondo Vianello
Jimmy il Fenomeno
Nico Rienzi
Rossana Canghiari