Superman Returns is only Spacey's second film in three years

In the first two Superman films - which director Bryan Singer has described as providing a "vague backstory" to Superman Returns - Luthor was played by Gene Hackman as a more comic role.

But while Spacey maintains the look of Hackman's Luthor, he gives the sinister real estate dealer a harder, darker personality, explained by his five years in prison.

"The element that Bryan Singer and the writers wanted to introduce into this film was to make Lex Luthor in this incarnation much more vicious, tough, scary - in a sense, to try to make him a real nemesis for Superman," Spacey said.

"He is not just a comic foil - there are moments in the movie, where Superman is at his most vulnerable, when you actually think Lex Luthor is going to win.

"That's a darker, newer element in this incarnation."

New challenge

Superman Returns keeps a number of elements of the original films - including the same music theme, and using unscreened footage of the now deceased actor Marlon Brando, who starred in the 1978 film as Superman's father.

Director Singer has said that his attraction to working on Superman Returns was much more to do with his love of the films than the comic books.

Lex is a much darker, more Machiavellian character than we've seen - at least in the film incarnations Kevin Spacey

"I don't think Bryan is heavy-handed about it, I just think he is recognising what has always been a part of the Superman myth," Spacey said.

"But he has also tried to mature it, in that the characters have been given real-world modern problems. Lois Lane is a single mother in a relationship, dealing with, effectively, an old boyfriend who comes back.

"Lex is a much darker, more Machiavellian character than we've seen - at least in the film incarnations."

Spacey added that the film and its iconic central character have been interpreted in a number of different ways worldwide.

He said that in Mexico, for example, he has dealt with a number of questions about Superman being a Christ-like figure; others see allegories with the Old Testament story of Moses.

Superman Returns is the first film Spacey has appeared in since 2004's Beyond The Sea, partially because of the work he has been doing as artistic director of the Old Vic theatre in London.

His next film is not expected until Christmas 2007 - when he will appear in Fred Claus, about the brother of Santa.

"To me, life is a banquet," Spacey said.