Two years ago the High Court in London threw out Mr Lucas's claim that Andrew Ainsworth, who created the original Stormtrooper costumes for the 1977 film, had breached copyright by selling replica outfits created from his original moulds.
While acknowledging Mr Lucas's claim under US law, the court ruled that the costumes had a "utilitarian purpose" as props and were not artworks, so were not covered by English copyright law.
Mr Lucas's counsel have told the Supreme Court that by accepting employment on the film, it was implied that Mr Ainsworth could not retain copyright of objects he created for it.
A ruling is expected in the next few months.
