John Wayne's heirs are suing an American university which they say is obstructing efforts to launch a proposed range of "Duke" alcoholic beverages.

The late star of countless classic westerns picked up the nickname as a small boy courtesy of firefighters in his Glendale, California home town: it was originally the name of the family dog, a huge Airedale terrier.

Wayne, born Marion Robert Morrison, who died in 1979 at the age of 72, and took the name John Wayne when he began to make his way in Hollywood in the 1930s.

The problem, say litigators, is that another famous Duke is preventing Wayne's heirs from fully exploiting their rights to his famous nickname. According to the Hollywood Reporter, Duke University in North Carolina has been arguing for more than a decade that the estate should not be allowed to market "Duke" restaurant services, gaming machines or celebrity licensing services. The institution's latest concern is with the Wayne estate's efforts to register the trademark for a line of spirits including bourbon, a favourite of the late star.

"Consistent with its policies and in order to prevent tarnishment of its brand, [Duke University] does not permit use of confusingly similar marks associated with unapproved goods or services, of uncertain quality and/or unregulated by [Duke University]," the institution reportedly told the US trademark office. "Consistent with its policies and in order to prevent tarnishment of its brand, [Duke University] does not permit use of confusingly similar marks associated with unapproved goods or services, of uncertain quality and/or unregulated by [Duke University]."

John Wayne Enterprises has now asked a US federal court to make a definitive ruling on the matter. "Duke University is not and never has been in the business of producing, marketing, distributing, or selling alcohol," states the complaint. "On information and belief, the actual and potential customer base of Duke University is vastly different from the customer base of JWE."

In particular, suggests the estate, Duke University is highly unlikely to ever market its own range of alcoholic beverages. Its complaint cites an example of a proposed "Duke" bourbon which features Wayne's image and signature along with the image of a shotgun shell casing. "Suffice to say, as is evident from Exhibit A, JWE regards Duke University's apparent belief that the JWE Marks cause confusion and dilution as ludicrous," says the estate.

It is not clear if Duke bourbon has yet made it onto shelves, but artisan distiller Monument Valley Distillers revealed in April that it was set to produce said branded beverage with the backing of Wayne's son, Ethan. The bourbon was due to join a limited-production Duke special reserve brandy which was introduced in May 2013..