Relatives of movie icon John Wayne have filed suit against officials at Duke University in Durham, North Carolina as part of a trademark battle over the actor's nickname 'The Duke'.

The two parties have been locked in a branding feud for almost a decade, but the legal fight heated up last year (13), when school bosses objected to Wayne's family applying to register 'Duke' for use in the liquor industry to produce a bourbon in the late actor's name.

University executives claimed the use of the name for booze may cause confusion among consumers and tarnish the school's brand, which is already established in the food and beverage markets.

Chiefs at John Wayne Enterprises have now taken the case to federal court, asking for a declaratory judgement giving them permission to use the Duke branding for bourbon, arguing, "Duke University is not and never has been in the business of producing, marketing, distributing, or selling alcohol.

"On information and belief, the actual and potential customer base of Duke University is vastly different from the customer base of Jwe."

The complaint, obtained by editors at The Hollywood Reporter, continues, "Duke University does not own the word 'Duke' in all contexts for all purposes. Duke is a common word that has been in use for centuries in a wide array of commercial and other applications wholly independent of Duke University. Yet by the actions alleged herein, Duke University seems to think it owns the word 'Duke' for all purposes and applications."