Complex sentence: Elwes also was a PA on "Octopussy" and "Superman", where he worked for a week assigned to Marlon Brando, and when Elwes introduced himself, Brando told him he was lying and that his (Elwes') name was actually Rocky.
Split into simpler sentences: Elwes also was a production assistant on the films "Octopussy" and "Superman", where he worked for a week assigned to Marlon Brando. When Elwes introduced himself, Brando told him he was lying and that his (Elwes') name was actually Rocky.